The Black Diamond Positron Screwgate is one of four carabiners in our test that we classify as "lightweight/compact lockers." Differentiated by their smaller size and weight from their larger full-sized counterparts, the compact locker is also made in an offset-D shape. This shape allows the 'biner to maintain a high strength-to-weight ratio, and allows it to perform well for certain uses, but does not allow for clipping lots of ropes or pairing well with a belay/rappel device. We like using larger lockers with wide baskets, like the Petzl Attache for these kinds of uses. The Positron Screwgate does work very well anywhere else that security is needed but a large rope-bearing basket is not optimal. Among the lightweight and compact lockers we tested, it is the largest, and also the heaviest, and so understandably received a lower score than those.
Black Diamond Positron Review
Cons: Squeeky gate and screw lock with lots of friction, larger, more expensive, and heavier than competitors
Manufacturer: Black Diamond
Our Analysis and Test Results
As a compact and lightweight locker, we compared the Positron closely to the Mad Rock Super Tech Keylock Screw, the DMM Phantom Screwgate, and the Edelrid Pure Slider throughout our testing process. Comparisons to these excellent products are not kind to the Positron. The Positron is the largest and heaviest of the four, but is still too small and not shaped correctly to be used like an HMS/pear shaped locker. It is a fair bit more expensive than the Mad Rock Super Tech, but again does not perform as well, calling into question its value. Most disappointing to us is the fact that much like the Black Diamond Rocklock Screwgate, the screw lock mechanism, as well as the pivoting gate itself, rub excessively, have friction inherent in the design or production, and squeak — a lot! Not present in any other lockers we tested, these flaws immediately cause us to question the quality of the construction, and leave us sold even more so on its competition.
Compact locking carabiners like the Positron Screwgate are useful in a variety of climbing and mountaineering situations, especially when the large size of an HMS 'biner is not required. We like using these compact lockers on climbing anchors, whether they are single or multi-pitch, on bolts or traditional protection. The thicker stock of the Positron does not get cut into as much as the lighter aluminum of the Edelrid Pure Slider. Using the Positron with an HMS locker when belaying a second climber with a plaquette style device like a Black Diamond ATC Guide is another appropriate use for this small but full strength locker.
The offset-D shape does allow for clove hitches to be used in a pinch, but Munter hitches bind up too easily in the tight curve between the spine and the basket. Using a pear-shaped locker like the Black Diamond RockLock Screwgate is better for hitches.
Ease of Unlocking and Locking
The Positron Screwgate uses a traditional, screw lock closure to secure the gate from opening. We cringe at the sound of metal on metal when screwing the gate open or closed, and it takes six half twists to lock or unlock the gate, roughly average among those tested. While we don't question the safety of these lockers, we also remember that when we tested the Positron two years ago we loved how smooth the action on the gate was, and now find it to be far and away the worst. Obviously, something in the production process has changed, but we demand the best for our money, and we will call out poor manufacturing where we see it! With perhaps the best reputation among climbing gear manufacturers, we are honestly a bit shocked to see this level of quality from Black Diamond.
Compactness and Weight
The Positron is the fourth smallest locker in this review, but larger than any of the other lightweight/compact lockers, weighing in at 15g heavier than the DMM Phantom Screwgate. Small lockers have their place on climbing harnesses for uses like attaching an auto-blocking friction hitch to backup your rappel, and the compact size can turn an otherwise bulky four locking carabiner/cordalette anchor setup into something a bit more manageable.
While the Positron is relatively light when compared to some of the lockers reviewed here, we must point out that for the same weight you could carry a fully functional locking carabiner like the Editors' Choice Petzl Attache or our Top Pick for Auto-locking, the Black Diamond Vaporlock Magnetron.
Despite the atrocious squeeking noise made when opening and closing the gate and screw lock mechanism on this locker (made the moment we pulled it out of the delivery box as well, for reference, not just after weeks of use in the real climbing world), we do not think there is any gate security issue beyond those inherent in the screwgate design. Like all screwgates, you must remember to lock the gate closed if it is to function as designed, and we advise you to orient the locker upside down when closed so that gravity and vibration cannot work to open it on their own over time.
With a gate opening width of 1.8 cm, the Positron ranks about average for a carabiner of its size and shape. It still does not have a wide enough opening to easily allow attachment to thick master points or multiple bight knots, but it is adequate to clip into bolt hangers, anchors made of thinner material and clip-in points of Gri-Gris and ascenders.
Compact lockers are a good option to save weight and reduce size. There may be no noticeable loss of function for their size in applications like anchor building, but if you need to clip into thicker things, or belay with a Munter hitch, they will not work as well as bigger, HMS shaped lockers. Carrying two or three of the larger sized lockers is usually enough, and filling out the rest of your locker needs with these compact biners is a good idea.
At $11, the BD Positron Screwgate is more expensive than the smaller, and lighter Mad Rock Super Tech Keylock Screw. It is not our first recommendation for this style of locker, but probably presents an okay value on its own, and can also be purchased in a three-pack for $31.95.
The Black Diamond Positron Screwgate locking carabiner is an all-around performer for all types of climbers. Whether you are looking for a locker that will help you set up a simple top rope anchor off of bolts, or are going big wall climbing and want to eliminate some of the bulk from your harness, the Positron can help you on your climbing adventures.
— Andy Wellman
Ad-free. Influence-free. Powered by Testing.
GearLab is founded on the principle of honest, objective, reviews. Our experts test thousands of products each year using thoughtful test plans that bring out key performance differences between competing products. And, to assure complete independence, we buy all the products we test ourselves. No cherry-picked units sent by manufacturers. No sponsored content. No ads. Just real, honest, side-by-side testing and comparison.Learn More