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The Best Locking Carabiners

The best use for a light and compact locker like the DMM Phantom is building multi-pitch anchors  as we have done here at Smith Rock. A collection of these can save you a lot of rack weight and are versatile enough that you probably only need to carry one or two HMS style lockers in addition to a few light and compact ones.
By Andy Wellman ⋅ Senior Review Editor
Thursday August 15, 2019
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Want to buy the best locking carabiner for your needs? We can help! We conducted in-depth research on over 40 of the top "lockers" available on the market today, eventually choosing 14 for extensive testing in this comparative review. Whether you are looking for the best options for building multi-pitch anchors, for belaying with a GriGri or ATC, or for rappelling, we have great recommendations for you. Our expert testers have decades worth of experience and put these locking carabiners through tests on the cliffs of Yosemite, Smith Rock, Red Rocks, and the Bugaboos to discover their hidden flaws and reveal their shining strengths. Our testing revealed the best choices for nearly any climbing discipline, knowledge that we happily share with you.


Top 14 Product Ratings

Displaying 1 - 5 of 14
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Awards Editors' Choice Award Top Pick Award Top Pick Award  Top Pick Award 
Price $15.95 at REI
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$27.95 at Amazon
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$15.50 at REI
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$17.95 at Backcountry
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$35.95 at REI
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Overall Score Sort Icon
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Pros Versatile, lightweight, relatively affordable, lots of gate clearance, gate security stripe.Light, auto-locking, versatileLight, small, least amount of revolutions needed for screwgate to lock or unlockVery quick and easy to unlock, auto-locks, very light and compactTriple-action auto-locking gate, stainless steel insert increases durability, internal spring bar prevents cross-loading or rotation.
Cons Screwgate can get stuck closed, aluminum I-beam construction wears out quicker than some.Can freeze shut, hard to open at times, locks shut on gear loopsExpensive compared to alternatives, the least amount of gate clearanceLocking mechanism not as secure as others, locking slider can block closure of gateHeavy, expensive, hard to unlock with one hand.
Bottom Line The best and most versatile locker at a reasonable price.Worthy of our Top Pick as the best auto-locking carabiner you can buy.Our favorite personal locker is great for building anchorsA unique tool for greater peace of mind while leadingAn ideal locker for belaying, and great choice for a top-rope anchor.
Rating Categories Petzl Attache Vaporlock Magnetron DMM Phantom Edelrid Pure Slider HMS Bulletproof Triple FG
Overall Utility (25%)
10
0
10
10
0
8
10
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7
10
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7
10
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9
Ease Of Unlocking And Locking (25%)
10
0
7
10
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5
10
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8
10
0
9
10
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4
Compactness And Weight (20%)
10
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8
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8
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10
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9
10
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4
Gate Security (20%)
10
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7
10
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9
10
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6
10
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4
10
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10
Gate Clearance (10%)
10
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10
10
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8
10
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3
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5
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9
Specs Petzl Attache Vaporlock Magnetron DMM Phantom Edelrid Pure Slider HMS Bulletproof...
Weight 57 g 56 g 41 g 43 g 87 g
Gate Closed Strength (KN) 22 24 24 23 25
Sideways Strength (KN) 7 7 9 8 9
Gate Open Strength (KN) 6 7 9 8 9
Gate Clearance 2.6 cm 2.2 cm 1.6 cm 1.8 cm 2.4 cm
Visual Locking Indicator? Yes Autolocking No Autolocking Autolocking
Carabiner Shape Pear/HMS Pear/HMS Offset-D Offset-D Pear/HMS
Lock Closure Type Screw-lock Magnetron Autolocking Screwgate Autolocking Slider Triple action Auto-lock or Screwgate

Best Overall


Petzl Attache


83
OVERALL
SCORE
  • Overall Utility - 25% 10
  • Ease of Unlocking and Locking - 25% 7
  • Compactness and Weight - 20% 8
  • Gate Security - 20% 7
  • Gate Clearance - 10% 10
Weight: 57g | Lock Closure Type: Screw-lock
The most functional and versatile locking carabiner
Largest amount of gate clearance makes for less hassle
Red safety stripe gives visual indicator gate is locked
Affordable
Screw gate gets stuck relatively easily
Not auto-locking

The Petzl Attache has long been a favorite locking carabiner, providing nearly unrivaled versatility for all types of climbing. It's pear shape means that it has a large basket that allows for clipping many ropes or other 'biners to it at once without overlap or pinching, and its very large gate clearance means that getting these items on or off is also a cinch. Its I-beam construction means that it's lightweight while also providing the strength that you would expect. This is a carabiner that can do everything, from belaying to rappelling, using as a master point or on the end of a daisy chain, and is both light and affordable.

There are very few downsides to the Attache, but one would be the fact that it is easy to tighten the screw locking mechanism down too tight, making it very difficult to unscrew. This can be avoided by recognizing that when you screw a locker closed, you are simply blocking the gate from opening, not actually joining the gate to the nose, so it doesn't need to be super tight. Also, try to screw it closed when it's un-weighted; doing so while it's under tension often makes it hard to unscrew when the weight is released. The Attache isn't auto-locking, meaning it's not fool-proof, but this fact is offset by a red visual indicator if the gate isn't locked. Screw gates also have other advantages, like ease of use with gloves on, and affordability. All in all the Petzl Attache is a locker that we can't live without, and recommend that every multi-pitch climber has two or three of these when they leave the ground — although it's easy to find additional uses if you have more!

Read Review: Petzl Attache

The Best Auto-locking Carabiner


Black Diamond Vaporlock Magnetron


Top Pick Award

$27.95
(7% off)
at Amazon
See It

75
OVERALL
SCORE
  • Overall Utility - 25% 8
  • Ease of Unlocking and Locking - 25% 5
  • Compactness and Weight - 20% 8
  • Gate Security - 20% 9
  • Gate Clearance - 10% 8
Weight: 56g | Lock Closure Type: Magrentron Auto-locking
Auto-locking means if it's closed, its locked
Very light for an HMS-style pear locker
Unique magnetic locking mechanism
Pricey
Harder to remove from harness loops than screw gates
Difficult to open while wearing gloves

Locking carabiners are the most secure way of attaching yourself to the rock or anchor, your belay device to your harness, or the rope to an anchor, with one caveat: they are only secure if they are actually locked. If you don't remember to screw the gate of your locker closed, then it isn't as secure as you think. The Black Diamond Vaporlock Magnetron is our favorite answer to this problem. It's an auto-locking carabiner, meaning if the gate is closed, it is automatically locked, so there is never a need to remember to lock it, or to check to see if it's locked. It uses a unique magnetic design to keep two hinges closed that block the gate from opening, which must be depressed on each side in order to release to open. Of the auto-lockers we tested for this review, we found this one to be the most versatile for all-purpose use, which is why chose to recognize it as our Top Pick.

The benefit of never having to worry about whether it's locked or not comes a few notable downsides. The Vaporlock Magentron is a bit pricey, a fair bit more expensive than the comparable Petzl Attache. It also requires you to squeeze the two hinge triggers every time you wish to open it, which can be a bit frustrating when it is sitting on a back gear loop of your harness. With thick gloves on, squeezing these triggers is undoubtedly harder than manipulating a screw gate locker. There is also the possibility that ice or magnetic dirt can block the magnets, so visual inspection, depending on when and where you are climbing, is still critical in ensuring a solid lock. These complaints are minor, however, when considering the peace of mind gained by simply knowing that the gate is locked. Pear shaped 'biners like this one are very versatile and can be used for almost any purpose, and we think everyone could find an appropriate use for at least two of them.

Read Review: Black Diamond Vaporlock Magnetron

Top Pick for Lightweight and Compactness


DMM Phantom


73
OVERALL
SCORE
  • Overall Utility - 25% 7
  • Ease of Unlocking and Locking - 25% 8
  • Compactness and Weight - 20% 10
  • Gate Security - 20% 6
  • Gate Clearance - 10% 3
Weight: 41g | Lock Closure Type: Screwgate
The lightest locking carabiner
The least amount of screwing to lock gate saves time
Buttery smooth gate and screw lock
Nearly double the price of the Mad Rock Super Tech
Not auto-locking

Stand at the bottom of any multi-pitch climb, clip the rack onto your harness and notice the significant amount of extra weight, not to mention clutter, that you will have to carry up the route with you. If your intended climb is close to your maximum climbing ability, then the weight of the rack could conceivably make a difference in whether you send or fall. Any opportunity to lighten the load helps you out, which is why we love compact, lightweight locking carabiners. How many lockers you need on a climb is up to you, but only one or two of these at most needs to be larger pear or HMS style lockers, the rest can, and should, be small lightweight lockers. We awarded our Top Pick to the DMM Phantom Screwgate because it is the best one you can buy. It is the lightest climbing rated locker we have ever used, and is also super quick to lock and unlock.

As long as you aren't trying to belay or rappel with these as your main locker, there is virtually no downside to using them. With their small size, you can't expect to clip a bunch of other 'biners to them, or ask them to hold multiple ropes or knots, but they can do literally everything else you would need a locker for, all while weighing less and taking up far less harness space than a typical locker. Anyone who loves multi-pitch climbing and wants only the best performance for when it matters should be in the market for three or four of the DMM Phantom Screwgates.

Read Review: DMM Phantom Screwgate

Top Pick for Durability


Edelrid HMS Bulletproof Triple FG


70
OVERALL
SCORE
  • Overall Utility - 25% 9
  • Ease of Unlocking and Locking - 25% 4
  • Compactness and Weight - 20% 4
  • Gate Security - 20% 10
  • Gate Clearance - 10% 9
Weight: 87g | Lock Closure Type: Triple Action Auto-lock
Triple action auto-locking offers unrivaled gate security
Stainless steel insert eliminates quick wearing and improves durability
Internal spring bar maintains orientation at all times
Heavy
Pricey

The friction of a weighted rope running over the inside of a locking carabiner can wear grooves into the aluminum in a surprisingly short amount of time. Exacerbating this effect is the fact that our ropes are often filled with abrasive dirt from playing outside all the time, and the fact that carabiners are more often being built with a narrower I-Beam shape to save weight while still offering the necessary strength. To combat the effects of premature wear, and the need for an early retirement, the Edelrid HMS Bulletproof Triple FG employs a stainless steel insert covering the basket of the carabiner where the rope typically runs. This feature is worthy enough to make it our Top Pick for Durability, and we highly recommend it for any high-wear situations, such as belaying with an ATC, rappelling, or for setting up top-rope anchors. It also has the notable perk of including a wire-gate keeper in the crotch that ensures that it always stays oriented correctly without becoming cross-loaded. Add to that the triple-action auto-locking gate mechanism, and you have one secure locking carabiner on your hands.

One of the few downsides to this locker is its weight, but the added security features are worth it. That said, on multi-pitch routes we would likely choose to carry a lighter HMS style locker, like the Petzl Attache for belaying with. We also discovered that the triple-action gate is difficult to open with one hand. With its bulletproof metal insert, this locker is ideal for use while rappelling, or as a master-point top roping anchor, in addition to regular belaying.

Read Review: Edelrid HMS Bulletproof Triple FG

Top Pick for Belaying with a GriGri


DMM Rhino


Top Pick Award

$15.95
(6% off)
at REI
See It

70
OVERALL
SCORE
  • Overall Utility - 25% 8
  • Ease of Unlocking and Locking - 25% 7
  • Compactness and Weight - 20% 6
  • Gate Security - 20% 6
  • Gate Clearance - 10% 8
Weight: 73g | Lock Closure Type: Screw-gate
A simple solution to keeping braking-assist belay devices oriented correctly
Versatile for any climbing application
Super smooth gate and locking mechanism action
Affordable
A bit heavy compared to other HMS or pear style lockers
Doesn't prevent ATC or tube-style belay devices from cross-loading

Belay devices should always be attached to the belay loop of a harness with a locking carabiner for security, but have the annoying tendency to flip sideways before catching a fall, cross-loading them along the wrong axis. In order to address this problem, many companies have engineered anti-crossloading carabiners specifically for belaying, and our favorite one that offers the simplest solution is the DMM Rhino. This beefy yet slick locker has a small "horn" on the outside of the spine that blocks braking assist devices, such as the Petzl GriGri or Trango Vergo from sliding off of the basket, where they are intended to stay to properly orient the forces of a potential fall. It also works great to keep pulley devices such as the Petzl Micro Traxion, or ascenders such as the Camp Lift, both commonly used while top-rope soloing, oriented along the proper weight bearing axis as well. While we tested the buttery smooth and very easy to use screw gate, this locker also comes with either double-action or triple action auto-locking gates as well.

While we love the Rhino due to its incredible simplicity and affordability, the downside compared to other anti-crossloading lockers such as the Black Diamond GridLock Magnetron or Mad Rock Gemini, which prevent biner shift by holding the belay loop in a fixed position in the crotch of the carabiner, is that it doesn't work with tube-style belay devices, whose keeper loop is plenty big enough to slide over the horn. We also point out that for being a simple HMS/pear shaped locker with a small horn added on, it is a bit heavy compared to the Petzl Attache, which is nearly the exact same shape. That said, the Rhino is just as versatile as the Attache, with the added benefit of keeping rope-catching devices oriented correctly. If we are belaying with a braking assisted device, or top-rope soloing, this is the locker we want on our belay loop.

Read Review: DMM Rhino Screwgate

Best Bang for the Buck


Mad Rock Super Tech Keylock Screw


Mad Rock Super Tech Keylock Screw
Best Buy Award

$7.95
(7% off)
at Amazon
See It

67
OVERALL
SCORE
  • Overall Utility - 25% 6
  • Ease of Unlocking and Locking - 25% 7
  • Compactness and Weight - 20% 9
  • Gate Security - 20% 6
  • Gate Clearance - 10% 4
Weight: 45g | Lock Closure Type: Screw-lock
VERY Affordable
Compact and lightweight
Easy to open and close
Small gate opening
Not large enough for belaying

The Mad Rock Super Tech locking carabiner is far and away the least expensive in this review. You could buy two of them for nearly the same price as a Petzl Attache, which is our favorite locker, and three of them for less than a single BD Vaporlock Magnetron. These 'biners are super light and very small, which combined with their low price, makes them worthy for loading up on for long alpine or free climbs.

The downsides to the Super Tech are basically the same as you would find with any compact lightweight carabiner. They are a modified D-shape, so they really only attach to one rope or item comfortably without overlapping and crowding taking place. They are also too small to use regularly for belaying or rappelling, but they can certainly work in a pinch if need be. However, a handful of these can really lighten and shrink your rack, and at the price there is no reason not to add three or four to your collection of Attaches.

Read Review: Mad Rock Super Tech Keylock Screw


Why You Should Trust Us


The expert tester who led this review is Andy Wellman. Andy has been climbing for over 23 years, and still has a handful of old, heavy, gold Petzl Attache locking carabiners, some of the very first that he bought while learning to climb in high school. A jack of all trades when it comes to climbing, Andy has traveled the world in search of climbing adventures, and continues to do so. He is the a former owner and publisher of Greener Grass Publishing rock climbing guidebooks, and is the author of Stone Fort Bouldering, a guidebook to one of the finest bouldering areas the US has to offer. He has passionately spent most of his life attuning himself to the intricacies of climbing gear while tackling all disciplines, from sport to big wall, bouldering to ice. He prefers to live near quality crags, and currently resides in Terrebonne, Oregon, just down the road from the tuff and basalt of Smith Rock.

The Frieno is best used with a gri-gri  as it is here getting ready for some single pitch trad cragging on basalt columns.
Mike Donaldson high up on the Beckey-Chouinard on South Howser Tower in the Bugaboos. Long alpine missions like this one necessitate each climber carrying a solid collection of locking carabiners for belaying  building anchors  and securing essential pieces of equipment.
Because it is auto-locking  meaning you cannot forget to lock the gate  it makes for a great anchor attachment point  as we are using it here on the anchor of pitch 4 to secure ourselves with a clove hitch.

Besides closely monitoring changes to rock climbing gear as they happen, Andy spent about 10 hours researching over 40 different locking carabiners before choosing the 14 for inclusion in this comparative review. He then tested them by using them on his adventures and climbing roadtrips, including jaunts to Red Rocks, Squamish, Index, the Fins, and the Bugaboos, besides all the climbing he does near his home in Oregon. He also conducted side-by-side tests, comparing different lockers one after the other for things such as the ability to tie knots to them easily (where gate clearance is often an issue), the ability to use them for multi-pitch anchors, as well as belaying with many different types of belay devices. He also forced his friends and climbing partners to use his gear, gathering outside opinions on what people like and don't. The end result is recommendations for all types of lockers, designed for all different purposes, provided by an expert tester.

Related: How We Tested Locking Carabiners

Analysis and Test Results


Locking carabiners, or simply "lockers" for short, are carabiners designed for climbing or rigging purposes that include a mechanism that keeps the gate closed. It is important to recognize that by locking the gate closed, you are not joining the gate to the nose to make the carabiner stronger; these carabiners are already extremely strong. Locking them simply prevents the gate from unwanted openings, securing whatever is inside the 'biner––whether a rope, knot, or sling––without allowing it to escape by accident. While lockers used to come in fairly simple designs, there are now countless varieties to choose from, each with an intended purpose and emphasizing certain traits, whether it's for belaying, rappelling, attaching the rope to a fixed piece or bolt, or countless other situations. Where, when, and what type of locker to use in any given situation is up to you, but the most common uses while climbing are on your belay and rappel device, as a master point of an anchor, as the connection point for a Personal Anchoring System (PAS) if you choose to use one, and to construct equalized multi-pitch anchors. For more information about where and when to use locking carabiners to climb safely, we recommend consulting a guiding service or climbing school.

You can never have too many lockers on a big wall climb. Here George is really happy he is attached with a couple of lockers for backup as he completes yet another lower-out cleaning the roof out of the black cave on the North America Wall  El Cap.
You can never have too many lockers on a big wall climb. Here George is really happy he is attached with a couple of lockers for backup as he completes yet another lower-out cleaning the roof out of the black cave on the North America Wall, El Cap.

For the purposes of this review, we tested three main styles of locking carabiners: those designed for belaying, HMS or pear-shaped lockers, and compact/lightweight lockers. These lockers come with a variety of different gate locking systems, and we made sure to test all the carabiners for all different purposes to give you the best picture of how well they perform. To accurately compare the lockers, we graded them according to five different metrics: Overall Utility, Ease of Locking and Unlocking, Compactness and Lightweight, Gate Security, and Gate Clearance. For each metric we awarded a score of 1-10, and in all cases scores were awarded in comparison to the other products. Each metric was then weighted based on how important it is to the overall function of the locking carabiner, and the scores were added together to come up with a product's overall score. Just because a product does not score highly in this review, does not mean it is a poor piece of equipment, and just because it scores highly does not mean it will be the best carabiner for your needs. Read on for descriptions of each grading metric, including how much it is weighted for the overall score, and which products perform best for that particular purpose.

Descending as a party of four on one rope while crossing glaciers in the Bugaboos. Tying in with multiple people in this way calls for locking carabiners  ideally used with alpine butterfly knots  and its best if each climber has an anti-crossloader for this usage.
Descending as a party of four on one rope while crossing glaciers in the Bugaboos. Tying in with multiple people in this way calls for locking carabiners, ideally used with alpine butterfly knots, and its best if each climber has an anti-crossloader for this usage.

Value


As any fledgling climber will soon come to realize, rock climbing is not an inexpensive sport to get started in. There is a sizeable investment in gear needed to enter even at the lowest rung of the ladder. To simply go gym climbing regularly a climber will need to purchase shoes, a harness, a chalk bag, and a belay device and locker, not to mention potentially investing in education or guiding, as well as a gym membership. Those who wish to explore further will need to spend many times more in equipment and learning, and even for an experienced climber, the need to continuously replace equipment like shoes, rope, harness, and a rack is significant. For this reason, value becomes a very important concern for climbers, not to mention the fact that a disproportionate amount of climbers are college students or dirtbags pinched for funds.


We don't grade products specifically for the value they offer, but we know it's a key factor in many purchase decisions. Both the Petzl Attache and the DMM Phantom Screwgate provide awesome performance at a reasonable price, while our Best Bang for the Buck winner, the Mad Rock Super Tech is far and away the most affordable, and gives pretty decent performance for that price.

Only a few pitches to go before the summit of the Beckey-Chouinard  belaying on a nice ledge  where a couple of lockers are used to build and equalize the all-gear belay  and one anti-crossloading belay locker is used for the safest belay.
Only a few pitches to go before the summit of the Beckey-Chouinard, belaying on a nice ledge, where a couple of lockers are used to build and equalize the all-gear belay, and one anti-crossloading belay locker is used for the safest belay.

Overall Utility


Overall Utility takes into account how well a locker performs at its intended purpose, as well as how versatile it is. In general, belay lockers, HMS-style pear lockers, and compact/lightweight D-lockers are designed for different purposes, so we first set out determining which were the best products at performing their intended purpose, compared to the competition. However, climbing is a game where you want to carry the least amount of stuff to aid in your performance, so having a locker that can do more than one thing well is a great advantage. So we also took into account the versatility of each locker, meaning its ability to be used in more than one situation without significant drawbacks.


Lockers are useful for any style of climbing  even single pitch cragging  as shown here. The Vaporlock Magnetron was so light it didn't bother us to take it to the top of the route to put on the chains as a secure master point for top-roping.
Lockers are useful for any style of climbing, even single pitch cragging, as shown here. The Vaporlock Magnetron was so light it didn't bother us to take it to the top of the route to put on the chains as a secure master point for top-roping.

Among all the lockers tested, the Petzl Attache does the best job at combining function and versatility. It is easy to use, is large enough to be used for nearly any purpose, has a very versatile pear-shaped basket, and is light enough to not make you think twice about bringing it on long climbs. For these reasons, it is the highest-rated HMS/pear-style locker. Among the lockers designed for belaying, we found the performance of the features on the Edelrid HMS Bulletproof Triple FG to be superior to the others. Its triple-action locking mechanism is super secure for belaying, it has an internal spring bar that keeps it properly oriented, and the stainless steel insert greatly increases longevity and decreases wear. While it is pretty heavy, we felt that it was also relatively versatile for use in anchor setups as well. The DMM Rhino is another favorite for belaying, as it is super versatile, affordable, and prevents most devices from cross-loading. Among the compact/lightweight lockers we found that the Edelrid Pure Slider and the DMM Phantom Screwgate were roughly equal in terms of overall utility. The Pure Slider didn't function as well as a locker as the DMM Phantom, but we found it to be more versatile in a number of different situations, so scored them the same. Overall Utility accounted for 25% of a product's final score.

Using a tiny and compact locker  like the black Super Tech shown here  as the second locker in an auto-block belay device  saves weight and space and works great. Using a locker with round stock in this situation will help the rope feed easier  but we prefer to carry less weight.
Using a tiny and compact locker, like the black Super Tech shown here, as the second locker in an auto-block belay device, saves weight and space and works great. Using a locker with round stock in this situation will help the rope feed easier, but we prefer to carry less weight.

Ease of Unlocking and Locking


The 14 lockers tested in this review include seven different styles of locking mechanism: the classic screw lock, a double-action twist auto-locker (Petzl Freino), a triple-action twist auto-locker (Edelrid HMS Bulletproof), a sliding locker (Edelrid Pure Slider), a magnetic auto-locker (BD Vaporlock and GridLock Magnetron), a screw gate with plastic safety bar (DMM Belay Master 2), and the double gate with single screw lock found on the Mad Rock Gemini. By repeatedly opening and closing these gates we learned that they range from very quick to relatively laborious, and super easy to requiring great dexterity. For this metric, gates that were quick and easy to open scored the highest, and ones that took longer and were more difficult scored lower. While screw gates require the same action to either lock or unlock, auto-locking 'biners snap closed and lock automatically, making them super easy to lock. However, they often require more dexterity to unlock, and can sometimes be annoying to unlock in order to simply remove them from a harness loop.


In order to unlock the Vaporlock Magentron  you must depress the bottoms of these two gold levers by squeezing them on either side of the gate  allowing them to come off their magnets and the gate to be pushed open.
In order to unlock the Vaporlock Magentron, you must depress the bottoms of these two gold levers by squeezing them on either side of the gate, allowing them to come off their magnets and the gate to be pushed open.

With its double-action twist auto-lock, the Petzl Freino was far and away the quickest and easiest locker to lock and unlock. It locks by itself every time in a snap, and to unlock you simply turn the gate ¼ turn and open it. This can easily be accomplished with one hand almost instantly. The Edelrid Pure Slider has a tiny little sliding lock that snaps over the tip of the nose when the gate is closed, and was the second quickest and easiest to unlock and lock. To unlock, simply slide the lock down with the thumb as you open the gate, and it then snaps closed and locks by itself (most of the time). Among screw gate lockers, the DMM Phantom is far and away the easiest and quickest. It needs only two full revolutions, or four half twists, of the screw gate to move from fully locked to fully unlocked, less than any other screw lock, and also features very smooth, buttery twisting action. We found the DMM Belay Master 2 and the Edelrid HMS Bulletproof Triple to be the slowest and most difficult to lock and unlock. In the case of the Belay Master 2, with its plastic clip that must be snapped in place after screwing closed, this is by design. But the dexterity needed to manipulate the triple action unlocking maneuver of the Edelrid Bulletproof was one we could not master with only one hand. Ease of Unlocking and Locking accounted for 25% of a product's final score.

Compactness and Weight


Gone are the days when carabiners were made of thick, heavy steel. Today most 'biners are made of an alloy of aluminum, which is far lighter than steel but can still be engineered to meet CE testing requirements for breaking strength. Also common these days are 'biners made with an I-beam construction, rather than a fully rounded rod of metal (although these are still common as well). I-beam design allows engineers to remove more metal while still meeting testing certifications, thereby further lightening the load of a single 'biner. Of course, using aluminum alloys in a lighter weight construction comes with the downside that these 'biners may show wear and need to be retired sooner, but for most climbers carrying less weight per item, multiplied by all of the many trinkets we need to carry with us up the rock, makes a noticeable difference in comfort, performance, and also fun, making weight something worth paying attention to.


With a rack this size  needed for aiding up the clean route Lunar Ecstasy is Zion National Park  saving weight on lockers (and every other piece of gear for that matter) can be a huge plus.
With a rack this size, needed for aiding up the clean route Lunar Ecstasy is Zion National Park, saving weight on lockers (and every other piece of gear for that matter) can be a huge plus.

Compactness is another factor to consider when choosing which lockers to buy. In many cases, you simply don't need a large locker that can adequately hold a Munter-hitch (like HMS style lockers are designed to do), and having a smaller locker will not only save weight once again, but also take up less space on your harness. Why would we want our climbing gear to be smaller if possible? Well, chimney your way up into the narrows of the Steck-Salathe in Yosemite, and I think you will find a good answer! To rate for compactness and lightweight, we measured each locker on our independent scale, counting grams to be more accurate, and then adjusted the scores accordingly depending on how small or large they were. Smaller and lighter meant higher scores.

Using the super light and compact Pure Slider as an anchor attachment on a multi-pitch bolted climb at Smith Rock. It clearly holds a hitch just fine  and here is shown also backed up with a personal anchor system daisy chain.
Using the super light and compact Pure Slider as an anchor attachment on a multi-pitch bolted climb at Smith Rock. It clearly holds a hitch just fine, and here is shown also backed up with a personal anchor system daisy chain.

The king when it comes to compactness and lightness is the DMM Phantom Screwgate, advertised as the lightest locking carabiner in the world. At 41g (1.45 oz.) it is lighter even than the Edelrid Pure Slider, which came in second (43g, 1.52 oz.), even though the Phantom comes with a screw gate, which is bulkier and more secure than the sliding lock mechanism of the Pure Slider. The Mad Rock Super Tech Keylock Screw (45g, 1.59 oz.), was a very close third to these other mega lightweights. Worth pointing out is that both the Petzl Attache (57g, 2.01 oz.) and the BD Vaporlock Magnetron (56g, 1.98 oz.) were barely any heavier, less than half an ounce, but offer more versatility. Compactness and lightweight account for 20% of a product's overall score.

Gate Security


Let's face it, if you didn't want the gate to stay locked closed, you would just buy a wiregate carabiner. While all of these lockers are going to stay closed once they are locked, some of us have slightly less trust in the gear, or more propensity to OCD behavior, than others, making gate security an important thing to consider. Auto-locking 'biners offer the most gate security because they lock automatically when they close. If the gate is closed, you can rest assured it is locked. Screw gate lockers, on the other hand, have a large caveat: you have to remember to screw them locked. Ask any experienced climber if they have ever forgotten to screw the gate of their locker closed and you are bound to hear some stories.


The Vaporlock Magnetron is the best auto-locker we tested  featuring double magnetized levers on each side of the gate that hold it locked closed. Its pear shape makes it super versatile and great for belaying.
The Vaporlock Magnetron is the best auto-locker we tested, featuring double magnetized levers on each side of the gate that hold it locked closed. Its pear shape makes it super versatile and great for belaying.

With its auto-locking closure and triple-action unlocking mechanism, the Edelrid HMS Bulletproof Triple FG is the most secure locker that we tested. The BD Vaporlock Magnetron, BD GridLock Magnetron, and the Petzl Freino are also auto-locking, but are a bit easier to open up, although it's virtually impossible to imagine a scenario where they would open on their own. Among the screw gate lockers, the DMM Belay Master features a plastic clip that snaps over the closed, locked gate, ensuring that it cannot unscrew or open on its own, and providing a solid visual indicator. The Petzl Attache and Mad Rock Gemini also come with a visual indicator, a solid red stripe across the gate that you can see if it is unlocked, but which becomes covered up when locked. Gate security accounts for 20% of a product's final score.

Screw gates have the unfortunate disadvantage of occasionally coming open on their own due to the vibrations of the rope or being knocked against the rope helping the screw the loosen and slip downwards. Orienting them upside down  as shown here  prevents this from happening as gravity keeps the gate closed.
Screw gates have the unfortunate disadvantage of occasionally coming open on their own due to the vibrations of the rope or being knocked against the rope helping the screw the loosen and slip downwards. Orienting them upside down, as shown here, prevents this from happening as gravity keeps the gate closed.

Gate Clearance


Different sizes and shapes of carabiners have different amounts of gate clearance. Gate clearance is the amount of space, at its narrowest point, between the gate and the nose when the gate is fully open. Gate clearance isn't a very important feature if you intend to simply clip one sling or rope through your locker, but when you are using a locker as a master point and have multiple ropes or knots clipped to it, then clearance can become an issue. In particular, if too many items are clipped to a single small locker, it can at times become difficult to get the gate open and slide a rope or knot out. This is why we often carry a couple of HMS-style large lockers to use as master points on multi-pitch anchors, and then top off our rack with far smaller and lighter lockers with much less carrying capacity and gate clearance.


With its large capacity  the Rocklock screwgate makes for an excellent master point for an equalized anchor  as it is easily able to hold a clove hitch  as shown here  or even two!
With its large capacity, the Rocklock screwgate makes for an excellent master point for an equalized anchor, as it is easily able to hold a clove hitch, as shown here, or even two!

Not surprisingly, smaller, D-shaped lockers have less gate clearance than larger, pear-shaped HMS style. We measured gate clearance with a ruler with the gate fixed open by a rubber band, and those with more clearance scored higher than those with less. We also documented the clearance of each locker in the specs table. The Petzl Attache, despite not being the single largest locker in our review, never-the-less has the most gate clearance at 2.6 cm. Close seconds were the largest lockers tested, the Black Diamond Rocklock Screwgate, as well as the Edelrid HMS Bulletproof Triple FG at 2.4 cm of clearance. Perhaps unsurprisingly, the DMM Phantom has the least amount of clearance, only 1.6 cm. As the least important feature contributing to a locker's performance, we weighted this metric at only 10%.

Doesn't get much nicer than topping out just before dark  here testing lockers on a quick late afternoon jaunt up the classic three pitch Zebra Zion at Smith Rock.
Doesn't get much nicer than topping out just before dark, here testing lockers on a quick late afternoon jaunt up the classic three pitch Zebra Zion at Smith Rock.

Conclusion


Climbing gear companies manufacture all sorts of locking carabiners, most of which are designed with a certain purpose or function in mind. Choosing the right locking carabiner starts by assessing the particular situations that you expect to use it, and then narrowing the search based upon the attributes that will lead to the best performance for those situations. Most climbers own many lockers, so buying a few different types and using them in different situations can help to make the selection process easier. Happy climbing!


Andy Wellman