Last updated
Clockwise from top left:
D-shaped wire gate
D-shaped straight gate
oval straight gate
pear-shaped auto locker
D-shaped screw locker.
Center is a standard carabiner rating. Assorted Biners.jpg
Clockwise from top left:
  • D-shaped wire gate
  • D-shaped straight gate
  • oval straight gate
  • pear-shaped auto locker
  • D-shaped screw locker.
Center is a standard carabiner rating.
Using a carabiner to connect to a rope Benutzung eines Karabiners.gif
Using a carabiner to connect to a rope

A carabiner or karabiner ( /ˌkærəˈbnər/ ) [1] is a specialized type of shackle, a metal loop with a spring-loaded gate [2] used to quickly and reversibly connect components, most notably in safety-critical systems. The word is a shortened form of Karabinerhaken (or also short Karabiner), a German phrase for a "spring hook" [3] used by a carbine rifleman, or carabinier, to attach his carabin to a belt or bandolier.



Carabiners are widely used in rope-intensive activities such as climbing, fall arrest systems, arboriculture, caving, sailing, hot air ballooning, rope rescue, construction, industrial rope work, window cleaning, whitewater rescue, and acrobatics. They are predominantly made from both steel and aluminium. Those used in sports tend to be of a lighter weight than those used in commercial applications and rope rescue.

Often referred to as carabiner-style or as mini-biners, carabiner keyrings and other light-use clips of similar style and design have also become popular. Most are stamped with a "Not For Climbing" or similar warning due to a common lack of load-testing and safety standards in manufacturing.

While any metal attaching link with a spring gate is technically a carabiner, the strict usage among the climbing community specifically refers only to those devices manufactured and tested for load-bearing in safety-critical systems like rock and mountain climbing, typically rated to 20  kN or more.

Carabiners on hot air balloons are used to connect the envelope to the basket and are rated at 2.5, 3, or 4 tonnes. [4]

Load-bearing screw-gate carabiners are used to connect the diver's umbilical to the surface supplied diver's harness. They are usually rated for a safe working load of 5 kN or more (equivalent to a weight in excess of approximately 500 kg). [5]



Carabiners come in four characteristic shapes:

  1. Oval: Symmetric. Most basic and utilitarian. Smooth regular curves are gentle on equipment and allow easy repositioning of loads. Their greatest disadvantage is that a load is shared equally on both the strong solid spine and the weaker gated axis.
  2. D: Asymmetric shape transfers the majority of the load on to the spine, the carabiner's strongest axis.
  3. Offset-D: Variant of a D with a greater asymmetry, allowing for a wider gate opening.
  4. Pear/HMS: Wider and rounder shape at the top than offset-D's, and typically larger. Used for belaying with a munter hitch, and with some types of belay device. The largest HMS carabiners can also be used for rappelling with a munter hitch (the size is needed to accommodate the hitch with two strands of rope). These are usually the heaviest carabiners.

Locking mechanisms

Carabiners fall into three broad locking categories: non-locking, manual locking, and auto locking.


Non-locking carabiners (or snap-links) [6] have a sprung swinging gate that accepts a rope, webbing sling, or other hardware. Rock climbers frequently connect two non-locking carabiners with a short length of webbing to create a quickdraw (an extender).

Two gate types are common:

  1. Solid gate: The more traditional carabiner design, incorporating a solid metal gate with separate pin and spring mechanisms. Most modern carabiners feature a 'key-lock nose shape and gate opening, which is less prone to snagging than traditional notch and pin design. Most locking carabiners are based on the solid gate design.
  2. Wire gate: A single piece of bent spring-steel wire forms the gate. Wire gate carabiners are significantly lighter than solid gates, with roughly the same strength. Wire gates are less prone to icing up than solid gates, an advantage in Alpine mountaineering and ice climbing. The reduced gate mass makes their wire bales less prone to "gate flutter", a dangerous condition created when the carabiner suddenly impacts rock or other hard surfaces during a fall, and the gate opens momentarily due to momentum (and both lowers the breaking strength of the carabiner when open, and potentially allows the rope to escape). Simple wiregate designs feature a notch that can snag objects (similar to original solid gate designs), but newer designs feature a shroud or guide wires around the "hooked" part of the carabiner nose to prevent snagging.

Both solid and wire gate carabiners can be either "straight gate" or "bent gate". Bent-gate carabiners are easier to clip a rope into using only one hand, and so are often used for the rope-end carabiner of quickdraws and alpine draws used for lead climbing.


Locking carabiners have the same general shape as non-locking carabiners, but have an additional mechanism securing the gate to prevent unintentional opening during use. These mechanisms may be either threaded sleeves ("screw-lock"), spring-loaded sleeves ("twist-lock"), magnetic levers ("Magnetron"), other spring loaded unlocking levers or opposing double spring loaded gates ("twin-gate").

  • Screw-lock (or screw gate): Have a threaded sleeve over the gate which must be engaged and disengaged manually. They have fewer moving parts than spring-loaded mechanisms, are less prone to malfunctioning due to contamination or component fatigue, and are easier to employ one-handed. They, however, require more total effort and are more time-consuming than pull-lock, twist-lock or lever-lock.
Carabiner with multiple combined auto lock and quick release, useful in via ferrata and arborist work, where two lanyards and carabiners are used Sicherheitskarabiner.jpg
Carabiner with multiple combined auto lock and quick release, useful in via ferrata and arborist work, where two lanyards and carabiners are used
  • Twist-lock, push-lock, twist-and-push-lock: Have a security sleeve over the gate which must be manually rotated and/or pulled to disengage, but which springs automatically to locked position upon release. They offer the advantage of re-engaging without additional user input, but being spring-loaded are prone to both spring fatigue and their more complex mechanisms becoming balky from dirt, ice, or other contamination. They are also difficult to open one-handed and with gloves on, and sometimes seize, getting stuck after being tightened under load, and being very hard to undo once the load is removed.
  • Multiple-levers: Having at least two spring loaded levers that are each operated with one hand.
  • Magnetic: Have two small levers with embedded magnets on either side of the locking gate which must be pushed towards each other or pinched simultaneously to unlock. Upon release the levers pull shut and into the locked position against a small steel insert in the carabiner nose. With the gate open the magnets in the two levers repel each other so they do not lock or stick together, which might prevent the gate from closing properly. Advantages are very easy one-handed operation, re-engaging without additional user input and few mechanical parts that can fail.
  • Double-Gate: Have two opposed overlapping gates at the opening which prevent a rope or anchor from inadvertently passing through the gate in either direction. Gates may only be opened by pushing outwards from in between towards either direction. The carabiner can therefore be opened by splitting the gates with a fingertip, allowing easy one hand operation. The likelihood of a rope under tension to split the gates is therefore practically none. The lack of a rotating lock prevents a rolling knot, such as the Munter hitch, from unlocking the gate and passing through, giving a measure of inherent safety in use and reducing mechanical complexity.



United States

American National Standards Institute/American Society of Safety Engineers standard ANSI Z359.1-2007 Safety Requirement for Personal Fall Arrest Systems, Subsystems and Components, section (for snap hooks and carabiners) is a voluntary consensus standard. This standard requires that all connectors/ carabiners support a minimum breaking strength (MBS) of 5,000 lbf (22 kN) and feature an auto-locking gate mechanism which supports a minimum breaking strength (MBS) of 3,600 lbf (16 kN).

See also

Related Research Articles

<span class="mw-page-title-main">Knot</span> Method of fastening or securing linear material

A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bends, loop knots, and splices: a hitch fastens a rope to another object; a bend fastens two ends of a rope to each another; a loop knot is any knot creating a loop; and splice denotes any multi-strand knot, including bends and loops. A knot may also refer, in the strictest sense, to a stopper or knob at the end of a rope to keep that end from slipping through a grommet or eye. Knots have excited interest since ancient times for their practical uses, as well as their topological intricacy, studied in the area of mathematics known as knot theory.

<span class="mw-page-title-main">Butterfly loop</span> Knot used to form a fixed loop in the middle of a rope

The butterfly loop, also known as lineman's loop, butterfly knot, alpine butterfly knot, Swiss loop and lineman's rider, is a knot used to form a fixed loop in the middle of a rope. Tied in the bight, it can be made in a rope without access to either of the ends; this is a distinct advantage when working with long climbing ropes. The butterfly loop is an excellent mid-line rigging knot; it handles multi-directional loading well and has a symmetrical shape that makes it easy to inspect. In a climbing context it is also useful for traverse lines, some anchors, shortening rope slings, and for isolating damaged sections of rope.

Climbing protection is any of a variety of devices employed to reduce risk and protect others while climbing rock and ice. It includes such items as nylon webbing and metal nuts, cams, bolts, and pitons.

<span class="mw-page-title-main">Traditional climbing</span> Style of rock climbing

Traditional climbing is a style of rock climbing in which the climber places all the necessary protection gear required to arrest any falls as they are climbing, and then removes it when the pitch is complete. Traditional bolted aid climbing means the bolts were placed while on lead and/or with hand drills. Traditional climbing carries a higher level of risk than bolted sport climbing, as the climber may not have placed the safety equipment correctly while trying to ascend the route; for some of the world's hardest climbs, there may not be sufficient cracks or features in the rock that can accept protection gear, and the climb can only be safely attempted by bolting as a sport climb.

This is an index of topics related to climbing.

<span class="mw-page-title-main">Quickdraw</span> Piece of climbing equipment used by rock and ice climbers

A quickdraw is a piece of climbing equipment used by rock and ice climbers to allow the climbing rope to run freely through protection such as a bolt anchors or other traditional gear while leading.

<span class="mw-page-title-main">Glossary of climbing terms</span> List of definitions of terms and concepts related to rock climbing and mountaineering

This glossary of climbing terms is a list of definitions of terms and jargon related to rock climbing and mountaineering. The specific terms used can vary considerably between different English-speaking countries; many of the phrases described here are particular to the United States and the United Kingdom.

<span class="mw-page-title-main">Rock-climbing equipment</span>

A wide range of equipment is used during rock or any other type of climbing that includes equipment commonly used to protect a climber against the consequences of a fall.

<span class="mw-page-title-main">Abseiling</span> Rope-controlled descent of a vertical surface

Abseiling, also known as rappelling, is the controlled descent of a steep slope, such as a rock face, by moving down a rope. When abseiling the person descending controls their own movement down the rope, in contrast to lowering off in which the rope attached to the person descending is paid out by their belayer.

<span class="mw-page-title-main">Belaying</span> Rock climbing safety technique using ropes

Belaying is a variety of techniques climbers use to create friction within a climbing system, particularly on a climbing rope, so that a falling climber does not fall very far. A climbing partner typically applies tension at the other end of the rope whenever the climber is not moving, and removes the tension from the rope whenever the climber needs more rope to continue climbing.

<span class="mw-page-title-main">Munter hitch</span> Adjustable knot used control friction in a belay system

The Munter hitch, also known as the Italian hitch, mezzo barcaiolo or the crossing hitch, is a simple adjustable knot, commonly used by climbers, cavers, and rescuers to control friction in a life-lining or belay system. To climbers, this hitch is also known as HMS, the abbreviation for the German term Halbmastwurfsicherung, meaning half clove hitch belay. This technique can be used with a special "pear-shaped" HMS locking carabiner, or any locking carabiner wide enough to take two turns of the rope.

Kernmantle rope is rope constructed with its interior core protected by a woven exterior sheath designed to optimize strength, durability, and flexibility. The core fibers provide the tensile strength of the rope, while the sheath protects the core from abrasion during use. This is the only construction of rope that is considered to be life safety rope by most fire and rescue services.

<span class="mw-page-title-main">Bachmann knot</span> Type of knot

The Bachmann hitch is a friction hitch, named after the Austrian alpinist Franz Bachmann. It is useful when the friction hitch needs to be reset quickly or often or made to be self-tending as in crevasse and self-rescue.

<span class="mw-page-title-main">Prusik knot</span> Type of knot

A Prusik is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord used to tie the hitch and the hitch itself, and the verb is "to prusik". More casually, the term is used for any friction hitch or device that can grab a rope. Due to the pronunciation, the word is often misspelled Prussik, Prussick, or Prussic.

In rock climbing, an anchor can be any device or method for attaching a climber, a rope, or a load above or onto a climbing surface—typically rock, ice, steep dirt, or a building—either permanently or temporarily. The intention of an anchor is case-specific but is usually for fall protection, primarily fall arrest and fall restraint. Climbing anchors are also used for hoisting, holding static loads, or redirecting a rope.

<span class="mw-page-title-main">Aerial silk</span> Aerial acrobatics

Aerial silks is a type of performance in which one or more artists perform aerial acrobatics while hanging from a fabric. The fabric may be hung as two pieces, or a single piece, folded to make a loop, classified as hammock silks. Performers climb the suspended fabric without the use of safety lines and rely only on their training and skill to ensure safety. They use the fabric to wrap, suspend, drop, swing, and spiral their bodies into and out of various positions. Aerial silks may be used to fly through the air, striking poses and figures while flying. Some performers use dried or spray rosin on their hands and feet to increase the friction and grip on the fabric.

<span class="mw-page-title-main">Climbing rope</span> Rope used to secure climbers

A climbing rope is a rope that is used in climbing. It is a critical part of an extensive chain of protective equipment used by climbers to help prevent potentially fatal fall-related accidents.

<span class="mw-page-title-main">Garda hitch</span>

The Garda Hitch is a class of climbing knots known as ratcheting knots for their ability to let the rope move in one direction, but not in the other. This class of knots has many uses in climbing and mountaineering, for example in a pulley system where a load is being hauled up a cliff, the Garda hitch prevents the load from slipping when the pulley system is reset.

<span class="mw-page-title-main">Radium release hitch</span>

A radium release hitch is a load-releasing hitch using 3:1 mechanical advantage which is used in a two-rope technical rescue system. The Radium Release Hitch allows a load to be transferred from one rope to another and is commonly rigged into the belay line prior to the operation of a two-rope technical rescue system.


  1. Wells, John C. (2008). Longman Pronunciation Dictionary (3rd ed.). Longman. ISBN   978-1-4058-8118-0.
  2. "Climbing Dictionary & Glossary". Archived from the original on 2007-01-03. Retrieved 2006-12-05.
  3. Harper, Douglas. "karabiner". Online Etymology Dictionary .
  4. "Cameron Balloons Maintenance Manual (refer to section 6.6.4)" . Retrieved 2015-03-28.
  5. Diving Advisory Board. Code Of Practice Inshore Diving (PDF). Pretoria: The South African Department of Labour. Archived from the original (PDF) on 9 November 2016. Retrieved 16 September 2016.
  6. "Climber's Club Journal" (PDF). Climber's Club. Retrieved 24 April 2005.
  7. "EN12275 and UIAA-121 testing protocols" (PDF). Professional Association of Climbing Instructors. Archived (PDF) from the original on 2022-10-10. Retrieved 5 December 2017.