The Black Diamond Positron Screwgate is one of two carabiners in our test that we will classify as "compact lockers." Differentiated by their smaller size and weight from their larger full-sized counterparts, the compact locker is typically 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 Am'D 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. It is a more durable compact locker than the Edelrid Pure Screw, though at a heavier weight.
Black Diamond Positron Review
Compare prices at 3 resellers Pros: Compact, durable, keylock nose
Cons: Weighs more than other compact lockers, not as functional as pear-shaped designs
Manufacturer: Black Diamond
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Our Analysis and Test Results
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 Screw. Using the Positron with an HMS locker when belaying a second climber with a plaquette style device like a Black Diamond ATC Guide was 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 bound up too easily in the tight curve between the spine and the basket. Using a pear-shaped locker like the Black Diamond RockLock Screwgate would be better for hitches.
Ease of Locking and Unlocking
The Positron Screwgate uses a traditional, screw lock closure to secure the gate from opening. We like how smooth the screwing action is, although it takes five twists to lock the gate, more than many other in the review. There is not a lot of free play in the screw gate, a notable feature that helps keep grit, snow, and ice out of the locking mechanism and keeps it working smoothly in variable conditions.
This contender is the second smallest locker in this review, only slightly larger than the Edelrid Pure Screw. 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.
The Positron is relatively light when compared with the rest of the options we reviewed, but for the same weight you could carry a fully functional locking carabiner like the Editors' Choice Petzl Attache or Black Diamond Vaporlock Magnetron.
With a gate opening width of 2.2 cm, the Positron has a good-sized clearance 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.
Gate Hang Up
Using a keylock nose that sweeps cleanly away from the basket, the Positron is easy to clip into bolt hangers and other small metal objects without snagging or hanging up. It did not take nearly as much effort to clip weighted anchor strands as it does with a notched gate like that found on the Omega Pacific ISO Locking Standard D.
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 that the similar sized, though much lighter Edelrid Pure Screw. It is made of more durable material and will last longer, though, and has a larger gate opening, making it a bit more functional overall. It is an okay value on its own, but 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 deserves a spot on your gear loop.
— Ryan Huetter