Climbing Carabiners Types: A Complete Guide to Locking, Non-Locking, and Specialty Carabiners

Climbing carabiners fall into three groups: non-locking connectors for quickdraws and racking, locking carabiners for belays and anchors, and specialty shapes like ovals and pears for pulleys, hitches, and descenders.

The difference between the two families comes down to one moving sleeve and a few kilonewtons of margin — and getting the pairing wrong is where the real risk lives. Below: the categories, the numbers from Petzl’s spec sheets, and the shape logic that decides which connector goes where.

The type code on the side — Type B for basic, plus specialty classifications — tells you more about how it’s meant to load than any marketing copy.

Locking vs. Non-Locking: What Actually Changes

Non-locking carabiners clip fast and are designed for applications where the gate rarely opens unexpectedly; locking carabiners add a sleeve that must be manually or automatically secured before loading.

A non-locking gate can roll open under a rope’s movement, a bolt hanger’s edge, or a sling brushing past. That’s fine on a quickdraw where clipping speed wins and the system is redundant, but it’s a fail condition anytime the connector is the only holding point — belay devices, anchor master points, rappel setups, and lanyard ends all require a locked gate.

Petzl’s range shows where the split sits. The Petzl SPIRIT is a 37 g aluminum non-locker rated 23 kN along the major axis, 7 kN minor axis, and 8 kN open gate. Its straight-gate version has a 21 mm opening; bent-gate models open to 24 mm. The 23 kN major-axis figure is roughly two and a half times the 8 kN open-gate rating.

Locking models swap speed for security. Screw-lock sleeves can work loose during prolonged use on the same anchor, so check the sleeve before every load.

Carabiner Shapes and What Each One Does

Oval carabiners center wide hardware, pear shapes widen the basket for belay stations, and D shapes direct load toward the spine — the three geometry families behind almost every climbing connector.

The oval’s symmetry keeps pulleys, ascenders, and wide-bodied devices tracking straight. Petzl’s non-locking OK (70 g, 25 kN major, 8 kN minor and open gate, 22 mm opening) is built for that, and it’s compatible with the CAPTIV positioning bar, which holds the connector along its major axis and limits cross-loading.

Pear shapes — the WILLIAM for belay stations and Munter hitches, the ATTACHE with its round-stock basket for smoother rope handling — give you a wider basket to work multiple strands. D shapes like the Am’D and compact Sm’D push load toward the strong side of the frame instead of sitting off-axis.

For tested picks across these categories, the best carabiners for climbing roundup breaks down models side by side.

When a Specialty Carabiner Is the Only Right Choice

Specialty connectors — ovals, multidirectional semicircles, friction-spur models, and position-bar variants — exist because some systems demand geometry a standard D or pear can’t provide.

Petzl’s FREINO Z includes a friction spur for the STOP and SIMPLE descenders, letting rappel friction be added or removed in a controlled way. The OMNI’s multidirectional semicircle works where load direction isn’t predictable, such as certain anchor link connections. The VERTIGO WIRE-LOCK is built for a specific lanyard system and shouldn’t be swapped for a generic wire-gate model.

The rule that overrides convenience: never substitute a non-locking carabiner where the manufacturer specifies a locking one. Petzl’s DUAL CONNECT ADJUST requires two Sm’D TWIST-LOCK-type locking carabiners (not included with the lanyard), and substituting an oval or a different lock type voids the intended setup.

Locking mechanisms and specialty features drive the spread, not metal volume.