Which climbing carabiner should you pick for the job?
A locking carabiner is chosen on what you're going to do with it, not on its spec sheet. Three questions narrow it down.
Is a rope going to run through it? That's the most important question and the one people ask least. A carabiner with a double-action auto-locking gate shuts and locks on its own in two moves: fast, intuitive, no sleeve left half done. The trade-off is that it stays with static connections — the ones where the rope doesn't move inside the carabiner. As soon as a rope runs through, repeated friction can act on the sleeve and cause it to open accidentally, and that's the territory of the triple-action auto-lock. The screw-lock carabiner runs into the same limit: you lock it by hand — screwed all the way down, no thread showing — and a running rope can act on that same sleeve. Beal goes as far as advising against a screw-lock for clipping a belay device: the instructions for its Air Force devices call for a locking carabiner, loaded along its major axis, gate closed. Before you pair a screw-lock with yours, read the instructions that came with it.
Which shape? An asymmetric shape like the Be Link Bi-Matic's stays oriented on its own at the end of a lanyard and at the anchor. A pear shape, the HMS, is built to work with a Munter hitch. A symmetric shape goes with pulleys and aid climbing. Those families line up with the classes in EN 12275: B for general use, H for the pear, K for via ferrata, X for the symmetric one.
Which standards? A climbing carabiner falls under EN 12275:2013 (mountaineering, climbing, caving, via ferrata). A connector meant for work at height falls under EN 362:2004. Some models, the Be Link Bi-Matic among them, meet both, which opens up sport use and professional use. In both standards, class B means a basic connector for general use.
And weight? It counts mainly when you carry a lot of them. For one or two carabiners on the harness, handling matters more, along with the gate opening — 20 mm on this one — and how easy it is to work with gloves or cold hands. A Keylock nose keeps it from hanging up as you clip and unclip.
Either way, you only get the rated strength with the carabiner closed, locked and loaded along its major axis. To round out your belay chain, take a look through our belay gear and ropes.
