Key takeaways
- A locking carabiner has a gate that secures shut, preventing accidental opening.
- Used for safety-critical links: belaying, rappelling, anchors, and personal connections.
- Types: manual screwgate (you twist a sleeve) and automatic/auto-locking (locks itself).
- Always lock it and check it; an unlocked locker offers no more protection than a non-locker.
What a locking carabiner is
A locking carabiner — a ‘locker’ — is a carabiner whose gate can be secured shut by a sleeve or mechanism, so it can’t accidentally open under load or by rubbing against the rock. That extra security makes it the right choice for the connections where an open gate could be catastrophic.
Types
- Screwgate (manual) — you twist a threaded sleeve to lock/unlock; simple and reliable, but you must remember to do it.
- Auto-locking (automatic) — locks itself when the gate shuts, often needing two or three actions to open; removes human error but is slower to operate.
Setting up to belay, a climber clips their belay device to the harness belay loop with a locking carabiner and screws the sleeve shut — then double-checks it’s locked, because an unlocked locker protects no better than a plain one.
When to use a locker
Use a locking carabiner for any safety-critical, single-carabiner connection: belaying, rappelling, clipping into anchors, and personal tethers. For connections that can’t easily unclip — like the ends of a quickdraw — non-locking carabiners are standard.
The bottom line
A locking carabiner adds a crucial margin of safety wherever an open gate would be dangerous — belaying, rappelling, anchors, and personal connections. Choose screwgate for simplicity or auto-locking to eliminate forgetting, but either way the rule is the same: actually lock it and check it, because an unlocked locker is just a heavier non-locker.
Frequently asked questions
What is a locking carabiner?
A locking carabiner is a carabiner whose gate can be locked shut — by a screw sleeve or an automatic mechanism — so it can't accidentally open. This makes it the safe choice for critical connections where an open gate could cause a serious accident, such as attaching a belay device or clipping into an anchor.
What's the difference between screwgate and auto-locking carabiners?
A screwgate (manual) locker has a threaded sleeve you twist by hand to lock and unlock — simple and reliable, but you must remember to lock it. An auto-locking carabiner locks itself when the gate closes (often needing two or three actions to open), removing the human error of forgetting to lock, at the cost of being slower to operate.
When should you use a locking carabiner?
Use a locker for any safety-critical, single-carabiner connection: attaching your belay or rappel device, clipping into anchors, connecting to the rope or a personal tether, and rigging. For connections that can't easily come unclipped, like the ends of a quickdraw, non-locking carabiners are standard.
Sources
- Connectors & carabiners — UIAA
- Climbing safety gear — American Alpine Club