Locking vs Non-Locking Carabiners
When to use each, full comparison table, and quick-answer guide for every climbing application.
The simple rule: if a single carabiner failure would cause an injury, use a locker. If the system has redundancy or the load is non-critical, a non-locking biner is faster and lighter.
A typical climbing rack carries both. Two or three lockers for belay, anchor, and personal anchor work — twelve to twenty non-lockers for quickdraws and gear racking. This page covers when to use each, the trade-offs, and the four common locking mechanisms.
Side-by-Side Comparison
| Aspect | Locking | Non-Locking |
|---|---|---|
| Gate security | Locked closed via screw, twist, or auto-lock — cannot accidentally open. | Spring-loaded gate; can be pushed open by rope, rock, or gear pressure. |
| Weight | Heavier — typically 60-100g per biner due to lock mechanism. | Lighter — wire-gates as low as 25-35g. |
| Speed of use | Slower — must screw or twist open and lock again. | Instant — clip and go. |
| Cost | More expensive — typically $12-25. | Cheaper — typically $7-15. |
| Where used | Belay attachment, anchor master points, personal anchors, rappel devices, top-rope anchors. | Quickdraw rope-end and bolt-end, gear racking, accessory clipping, extending placements. |
Quick Answers by Use Case
Belaying
LOCKING — single point of failure between you and the climber. Always locking.
Anchor master point
LOCKING — same logic. The carabiner you trust your life to should be locked.
Quickdraw (sport climbing)
NON-LOCKING — pairs of non-lockers per quickdraw. Speed and weight win out over individual gate security; redundancy comes from multiple bolts.
Personal anchor system
LOCKING — connects you to the anchor.
Trad gear racking
NON-LOCKING — quickdraw-style biners on a sling for racking cams and nuts.
Top-rope anchor at a crag
LOCKING — usually two opposite-and-opposed lockers.
Bouldering accessories (chalk bag clip, brushes)
NON-LOCKING — small wire-gate biners. No load-bearing role.
Rappel device attachment
LOCKING — connects rappel device to harness.
Types of Locking Mechanisms
If you've decided on a locker, choose the lock action based on your priorities.
Screw-gate
Manual screw collar. Cheap, reliable, simple. Slowest to use. Standard belay locker.
Twist-lock (auto-lock)
Automatically locks when released. Two-action open (twist + push). Faster, more secure than screw-gate.
Triple-action
Three-action open (lift + twist + push). Maximum security, used in rope-rescue and via ferrata.
Magnetic auto-lock
Magnets pull two arms together to keep gate closed. Two-action open. Smooth, gritless action.
What Most Climbers Buy
- For belay: One pear-shape (HMS) screw-gate or twist-lock locker. Petzl Attache or Black Diamond RockLock are standards.
- For anchor: One or two D-shape lockers. Petzl Am'D Screw-Lock works.
- For quickdraws: Pre-built quickdraws with non-locking wire-gate biners on each end. Six to twelve quickdraws covers most sport routes.
- For gear racking: A handful of cheap non-locking wire-gate biners (Black Diamond MiniWire, Petzl Spirit).
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