What is a carabiner?
A carabiner (also spelled karabiner, and nicknamed krab, crab or biner) is a metal oval loop with a gate that opens on one side. Climbers use them to connect ropes, belay devices, quickdraws and protection to harnesses and anchor points.
They come in two main types: locking and non-locking. Locking carabiners have a mechanism that prevents the gate opening accidentally, making them essential for belaying and anchors. Non-locking carabiners are faster to clip and are typically used on quickdraws, for racking gear, or as runners on a route.
Locking vs non-locking carabiners
Locking carabiners give you security where it matters most. The locking feature—either a screwgate or twist-lock mechanism—stops the gate from opening under load or by accident. Use them whenever you're belaying, rigging anchors, or connecting critical components like your belay device to your harness.
Non-locking carabiners are designed for speed. They're lighter and quicker to clip, which is why climbers use them on quickdraws and for racking gear on their harness. The gate can be solid, bent (for easier rope clipping) or wire (lighter and less prone to freezing).
Carabiner shapes explained
HMS (or pear-shaped) carabiners have a wide, rounded top that works well with belay devices and Italian hitches. D-shaped carabiners place the load towards the stronger spine, making them efficient for most climbing applications. Oval carabiners load symmetrically and are often used with pulleys or when you need predictable orientation, though they're not as strong as D-shapes for their weight.
Gate types and what they're for
Solid gates are robust and familiar, but they can freeze in winter or buzz against rock. Bent gates make clipping the rope easier, so you'll usually find them on the rope end of a quickdraw. Wire gates are lighter, don't freeze as readily, and reduce gate flutter—the brief moment when a carabiner can unclip if the gate bounces open on impact. Many climbers now prefer wire gates for alpine routes and traditional climbing.
Choosing carabiners for your climbing
Match your carabiners to the job. For belaying and anchors, choose locking carabiners—screwgates are reliable and affordable, while twist-locks can be faster to operate. For sport climbing quickdraws, a solid or bent gate on the rope end speeds up clipping. Traditional climbers often carry a mix: lockers for the belay and anchor, wire gates for gear placements to save weight.
If you're starting out, look for good-value options that meet the same safety standards as premium models. Weight matters more on long alpine routes or when you're carrying a full traditional rack. For indoor climbing or short sport routes, durability and ease of use often count for more than saving a few grams.
Questions we get asked
How many carabiners do I need?
For indoor climbing, one or two locking carabiners for your belay device is enough to start. Sport climbers typically carry ten to fifteen quickdraws. Traditional climbers need more—often twenty or more carabiners to build anchors and rack protection.
Can I use any carabiner for belaying?
Always use a locking carabiner for belaying. The locking mechanism prevents the gate from opening accidentally, which is essential for your safety and your partner's.
What's the difference between a screwgate and a twist-lock?
Both lock the gate closed, but a screwgate uses a threaded sleeve you turn manually, while a twist-lock has a spring-loaded sleeve you twist and release. Twist-locks can be faster to operate but are usually a bit heavier and more expensive.
Are wire gate carabiners as strong as solid gates?
Yes. Wire gates meet the same safety standards and are often lighter. They also resist freezing and reduce gate flutter, making them popular for alpine and traditional climbing.
Can I use climbing carabiners for other activities?
Climbing carabiners are designed and tested to strict safety standards for climbing. While some people use smaller accessory carabiners for attaching gear to rucksacks, never use non-climbing carabiners (like keyring clips) for any load-bearing climbing application.
