Carabiners are lightweight, metal snap-links used by climbers for a wide variety of tasks. They come in a range of styles, sizes and designs. To choose and use them properly, you must first understand the differences between them.

Carabiner Basics

Carabiners are built to connect things together: a climber to his or her rope, a rope to a piece of protection, a collection of protection pieces to a climbing harness. Different climbing tasks require different kinds of carabiners.

To understand the most important variables, read on:

Shape Options

Oval Carabiner

Oval: Oval carabiners are the original style. They're versatile and affordable though not quite as strong as other shapes. Oval 'biners have smooth, uniform top and bottom curves to limit load shifting. They offer more gear-holding capacity than D-shape 'biners. Their symmetry permits them to be used for carabiner-brake rappels. Two reversed ovals, with opposing gates, can be substituted for 1 locking carabiner. They're ideal for aid climbing because they center loads at their curve; runners won't shift under load.

D Carabiner

"D" Shape: D-shaped 'biners are excellent for most kinds of climbing. They hold loads off-center toward the stronger, non-gated side, so D's are lighter than ovals of the same strength rating. Because of their shape just above the gate, they are also easier to clip into protection pieces.

Asymmetrical "D" Shape: Asymmetrical D's work like regular D's, but they're slightly smaller at one end to further reduce weight. Asymmetrical 'biners generally have larger gate openings than regular D's, which makes clipping them even easier. But they don't have as much inside room as similarly sized Ds or ovals.

Gate Options

Straight: Standard straight gates are by far the most common and are used on protection, bolts and quickdraws. They're perfectly straight from pivot point to end. Like most other types, they're spring-loaded to open easily when pushed, but close automatically when released.

Bent-Gate Carabiner

Bent-gate: These have a concave gate designed to make clipping a rope into it easier. The bent-gate design does not significantly affect strength or weight. But if not used properly, bent-gate carabiners can unclip from your rope. As with any other kind of climbing equipment, you must learn how to use bent-gate 'biners correctly in order to be safe.

Warning: Bent-gate 'biners should only be used on the end of the quickdraw or runner which the rope clips into. Never clip them directly to the protection.

Wire-Gate Carabiner

Wire-gate: Wire-gate 'biners use a loop of stainless steel wire for a gate. This wire loop creates its own spring mechanism as it pivots, decreasing overall weight and eliminating the need for extra parts found in conventional gates. Wire gate designs also allow for larger gate openings.

Although wire gates don't appear as strong as conventional styles, most are. They are also less likely to vibrate open during a fall due to the lower mass in the gate itself.

Locking or Nonlocking?

Locking Carabiner

Locking carabiners have gates that can be locked in the closed position to provide extra protection against accidental gate-openings. They feature either a manual (a.k.a. screwgate) or auto-locking system. A manual lock requires the user to screw the sleeve onto the gate to lock it. An auto-lock 'biner locks when the gate is closed.

Locking carabiners, though heavier than nonlocking models, are the only choice for use with a belay/rappel device. You should also consider using them at belay stations and at critical protection placements. They offer a more secure attachment and enhance your peace of mind.

Locking 'biners can be oval, D-shaped or asymmetrical.

Size and Weight

Carabiners come in a variety of sizes. Large 'biners are typically easier to handle, easier to clip (they have larger gate openings) and can hold more gear inside. They are commonly used with belay and rapel devices. Smaller 'biners are lighter and take up less room on your rack.

In general, the less weight you carry with you as you climb, the better. But lighter carabiners are not always best. Super-light carabiners often use narrower rod stock, which can mean lower gate-open strengths and shorter lifespans. Narrow 'biners can also cause more rope wear, since the narrow ends can act like edges, biting into your weighted rope as it slides past.

Know Your Needs

The key factor to consider when choosing carabiners? It is knowing what you'll be using them for. Different styles are designed for different tasks. If you're just starting out, ask a climbing instructor or an experienced salesperson for guidance on which styles to start with. More experienced climbers should consider your types of climbing, the kinds of protection you'll be clipping into and the tasks you'll need your 'biners to perform.

Once you've narrowed down your search, grab a few models and get a feel for how they fit in your hand, how easy they are to clip and unclip, and how smoothly the gates work. For locking 'biners, try locking and unlocking the gate a few times (with 1 hand). Choose models that feel good, operate smoothly and are easy to work with.

Carabiner Strength

Anatomy of a Carabiner


Carabiners are designed to be loaded along their long ("major") axis with their gates closed. When loaded correctly, all of the carabiners that REI carries are built strong enough to handle the loads found in normal climbing situations.

Unfortunately, carabiners can fail at loads well below their rated strength when they're used incorrectly or if they're loaded with their gates open.

Gate Lash

The dynamics of just about any climbing fall can cause "gate lash" (a momentary opening of a carabiner's gate caused by vibration or the spine hitting a solid object). Gate lash can reduce a 'biner's overall strength to its open-gate strength. It can occur when:

  • A gate's inertia overcomes the spring tension holding it in place
  • A gate collides with another object

To protect yourself against this type of carabiner failure, choose carabiners with locking gates and/or high gate-open strengths (REI provides both gate-closed and gate-open strength ratings for your convenience) and more importantly, learn how to use your carabiners correctly. Specific gate designs and/or stiff spring tensions may also reduce the risk of gate lash. Ask an experienced REI salesperson for recommendations.

Note: Because a falling climber is a mass accelerating under the pull of gravity, carabiner strengths are measured in kiloNewtons (kNs), a measure of force (mass times acceleration). For conversion purposes, 1 kN is approximately equal to 225 lbs. of force.

Shop REI's selection of carabiners.



A quickdraw consists of 2 carabiners attached with a loop of webbing. One carabiner attaches to the bolt hanger or loop on the protection; the other to the climbing rope. Why use these? A quickdraw allows more rope movement without dislodging protection.

For more information, see the REI Expert Advice article, Quickdraws, Sewn Slings and Bulk Webbing/Cord: How to Choose.

Shop REI's selection of quickdraws.

Use Your Carabiners Correctly

  • Carabiner strength is measured in force (mass x acceleration). A falling climber is a mass accelerating under the pull of gravity. As noted above, this force is measured in kiloNewtons (kN); one kiloNewton is approximately 225 lbs. of force.
  • Strength ratings assume proper use; improper use decreases strength.
  • Check gate action with each use to make sure it opens and closes quickly and easily. Be sure the nose and hinge of the carabiner operate and are not obstructed.
  • Do not allow the rope to run against the sleeve of a locking carabiner.
  • Place loads only along the major axis (the long way). A carabiner loaded along the minor (shorter) axis can fail in a fall.
  • Gate-open strength is less than half of a 'biner's gate-closed strength.
  • On nonlocking 'biners, avoid setups in which a rope can cross back and open a gate. With both straight- and bent-gate carabiners, a protruding nose can catch and open a gate. Use locking 'biners at all critical points.
  • You must check to see that your locking carabiner is properly locked with each use.

Regular carabiner inspection and care is critical. For more information, see the REI Expert Advice article, Carabiner Care.

Remember: Climbing safety is your responsibility. Expert instruction is absolutely essential if you're new to climbing and when trying new equipment.

All carabiners sold at REI conform to UIAA standards.

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