Locking Carabiner Buying Advice For Climbing: 6 Things to Look For

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Locking carabiners have evolved a lot in the last decade. They are lighter and are designed for more specialized tasks. There are few one-size-fits-all carabiners. Instead, there are certain carabiners that are best for belaying, rappelling, use in anchors and lightweight biners. Below, we look at key factors to use when choosing the best locking carabiner. – Chris McNamara

Lightness, Compactness

If you just are buying a carabiner for belaying at the gym or the crag, weight does not matter much. If you are climbing multi-pitch routes or doing alpine routes, every ounce is crucial. The difference between having six light locking carabiners like the Best Buy Mad Rock Super Tech Keylock Screw or Top Pick Wild Country Neon Keylock Screwgate Carabiner on your harness or six standard locking carabiners is big. More importantly, light biners are much less bulky like the small, compact Trango SuperFly Screwlock so they swing around less on your harness and don't get stuck as much in chimneys. The good news is there are more lightweight carabiners than ever. The challenge is finding a carabiner that can do everything you need at the right price. Most light biners work fine for general use, but do not excel at belaying, rappelling or use as a master point in an anchor due to their small size, except the Editor's Choice Petzl Attache 3D. You lose some functionality with most light carabiners so make sure the weight saving is worth it. We discovered that the manufacturer's quoted weight and the weight from our scale can differ by as much as five percent. This doesn't mean you should trust our weight more than the manufacturer's. But it does mean you should not get hung up on a few grams of difference when buying a light carabiner.

Gate Type: Screw-gate or Twist-lock?

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Black Diamond Rocklock Screwgate
There are two main gate types: twist-lock and screw-gate. A twist-lock carabiner like the Omega Pacific Jake is the fastest to lock and unlock because you can take it off and on with just one motion of your hand. For this reason they are ideal for gym climbing or cragging if you want to save time. The screw-gate carabiners take more turns to close and you must remember to close them (twist-lock carabiners have a spring and close on their own). However, a screw-gate carabiner can feel more secure in an anchor because it is less likely that the gate can open accidentally if the carabiner is moved into an awkward position. This problem is addressed in some carabiners that use a ball-lock mechanism like the carabiner below.

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Petzl Am'D

Screw-gate carabiners are usually 25 percent less expensive and lighter in weight. In general, twist-lock carabiners are best for belaying and rappelling and screw-gate carabiners are better for everything else.

When buying a screw-gate carabiner, consider how many twists it takes to open and close the gate. We generally prefer biners that take fewer twists because you save time like the large DMM Boa or smaller Wild Country Synergy. However, some people may feel safer if a carabiner takes more twists to open and close. Also, when carabiners are brand new, some gates will be more fluid. Some biners can be opened and closed with one precise flick of the fingers, which is convenient.

Because you have to remember to close a screw-gate carabiner, it's nice to have safety features like Petzl uses on many of their biners like the Petzl Am'D. They have a red stripe that disappears when the gate is closed. This helps remind you to lock the gate and also helps prevent over-tightening. Other manufacturers deal with the over-tightening issue by putting metal on the gate so that the gate stops the screw-gate mechanism before it hits the other side of the biner.

Gate Hangup

We prefer key-lock gates because they get hung up less on slings and bolt hangers like we found with the Black Diamond Mini Pearabiner or Wild Country Neon Keylock Screwgate Carabiner. Most carabiners now come with key-lock options and they generally don't cost more so there is no reason not to go the key-lock route. In addition, some key-lock carabiners are a little smoother to get on and off due to the angle of their key-lock; the smoother the angle the smoother the carabiner comes on and off. However, that is a pretty subtle distinction between key-lock carabiners. The main thing is to go key-lock when possible.

Number of Knots Held

If you use a carabiner in an anchor, especially as the master point, it's nice if the biner holds lots of ropes and slings like the Black Diamond Rocklock or the DMM Boa. Generally, the larger the carabiner, the better it is at holding lots of cord. That said, shape also plays a role. If a carabiner has a pear shape with a big area below the gate, then more ropes and slings will fit in. A D shape or oval shape generally holds a little less. Lightweight carabiners hold very few ropes and slings because of their compact size, which limits their versatility.

Rope Pull Smoothness

How smoothly a rope pulls through a carabiner is essential if you are belaying a second climber off the anchor using an auto-block belay device like the Petzl Reverso 4. The wider and rounder the stock of the aluminum, the smoother the rope will flow over it. In addition, carabiners like Petzl OK or Petzl Attache with more oval shapes or pear shapes generally keep the rope from contacting the spine and therefor have less drag. The other instance where rope pull smoothness is nice is with top rope anchors, where it is nice to have a smooth pull. Other than those situations, smoothness is less important compared to other factors like the gate performance, shape and weight.

Gate Clearance

We found gate clearance to be less important than how many ropes a biner will hold. In general, you are only clipping one rope or sling at a time and all gates work about the same. Only in very specialized applications like using a locking carabiner with a big pulley is gate clearance as big an issue.

Chris McNamara
About the Author
Chris is the founder of OutdoorGearLab and serves as Editor-in-Chief. Climbing Magazine once computed that three percent of Chris McNamara's life on earth has been spent on the face of El Capitan—an accomplishment that has left friends and family pondering Chris' sanity. He's climbed El Capitan over 70 times and holds nine big wall speed climbing records. In 1998 Chris did the first Girdle Traverse of El Capitan, an epic 75-pitch route that begs the question, "Why?" Outside Magazine has called Chris one of "the world's finest aid climbers." He's the winner of the 1999 Bates Award from the American Alpine Club and founder of the American Safe Climbing Association, a nonprofit group that has replaced over 14,000 dangerous anchor bolts. Chris is also the founder and lead author of the rock climbing guidebooks publisher, SuperTopo. He is a graduate of UC Berkeley. You can follow him on Facebook, Twitter or ChrisMcNamara.com. He also has two Lake Tahoe Vacation Rentals here and here.