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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

A carabiner or karabiner (/ˌkærəˈbnər/),[1] often shortened to biner or to crab, colloquially known as a (climbing) clip, 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 comes from the German Karabiner, short for Karabinerhaken, meaning "carbine hook,"[3] as the device was used by carabiniers to attach their carbines to their belts.


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-carabiners, 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 link with a spring-loaded gate is technically a carabiner, the strict usage among the climbing community specifically refers only to 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. Often preferred type for racking biners due to their symmetric shape.
  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.


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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").

Carabiner with multiple combined auto lock and quick release, useful in via ferrata and arborist work, where two lanyards and carabiners are used



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).


Hooks with a sprung, hinged gate, depicted on a horse's muzzle in the Codex Löffelholz folio 38v, about 1505
Rather poor depiction of a carabiner attached to a shoulder belt, from Johann Jacob von Wallhausen's Kriegskunst zu Pferdt, 1616

The first known hooks that had a sprung, hinged gate where the spring kept it closed (characteristics expected of a carabiner)[8] were depicted by Nuremberg patrician Martin Löffelholz von Kolberg in about 1505 in the Codex Löffelholz, in the Holy Roman Empire. These then became the clip used to hold a cavalry carbine or arquebus, with the earliest known mention of them being in 1616 by Johann Jacob von Wallhausen, in the Holy Roman Empire.[9] They were widely used in many European countries during the 17th century,[8] and typically had a belt attachment and swivel joint, much like a modern luggage strap or handbag strap. The load bearing latch was added in the 1790s,[8][10] for the British cavalry design. They were used for many other purposes during the 19th century,[8] such as for luggage straps, mining and connecting ropes. Some common designs first appeared during that time, including S-carabiners. Oval links, which had also appeared in 1485, also reappeared as carabiners. Screw gates and internal springs were developed. Prussian fire brigades began to use carabiners for connecting themselves to ladders in 1847,[11][8] and this became the modern gourd-shaped design by 1868.[12] German and Austrian mountaineers started using them during the late 19th century, with a mention of their use from 1879,[13] and their continued use for climbing by climbers in Saxon Switzerland.[8][14] The majority used gourd shaped carabiners which were created for mining or other utility purposes.[8][14]

The common myth suggesting that they were invented, created, designed, made or developed by German climber Otto "Rambo" Herzog has no basis in fact.[15][14] However, like many climbers before him, he did use them for some challenging climbs, and some new techniques. However, it is worth noting that he did not invent them, or develop any designs, and he was born long after other climbers were already using them. More designs were used by climbers during the 1920s, such as narrow pear shapes, mostly sold for general hardware.[8][14] During the late 1920s and early 1930s, carabiners were being sold for climbing,[14] with oval designs being popular during the 1930s. Hardened steel carabiners appeared in the 1930s. Prototype aluminium carabiners, the first dedicated climbing carabiners, were made first by Pierre Allain during the 1930s,[16][8] which were also the first offset D-shaped carabiner. Aluminium carabiners were first sold to the military in 1941,[17] which were the first commercial carabiners designed specifically for climbing. Slightly offset D-shaped carabiners were sold in the late 1940s, which became the standard offset D-shape which is now the most common in the 1950s.[8]

Chouinard Equipment introduced the 22 kN aluminium carabiner in 1968, though this strength had already been far surpassed by steel carabiners.[8] Wiregate carabiners were first patented in 1969, and were sold for maritime use.[8] They were first sold for climbing in 1996. The popular keylock, which avoids snagging, was developed around 1984–1987.[8]

See also


  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 3 January 2007. Retrieved 5 December 2006.
  3. ^ "carabiner". Dictionary.
  4. ^ "Cameron Balloons Maintenance Manual (refer to section 6.6.4)". Retrieved 28 March 2015.
  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 10 October 2022. Retrieved 5 December 2017.
  8. ^ a b c d e f g h i j k l m "Carabiner history". Retrieved 17 January 2024.
  9. ^ von Wallhausen, Johann Jacob (1616). Kriegskunst zu Pferdt. Holy Roman Empire: de Bry.
  10. ^ Turner, Pierre (2006). Soldiers' Accoutrements of the British Army 1750-1900. United Kingdom: The Crowood Press. pp. 36–37. ISBN 9781861268839.
  11. ^ von Quast, Ferdinand (1847). Notiz-Blatt des Architekten-Vereins zu Berlin. Prussia: Riegel. p. 47.
  12. ^ Magirus, Conrad Dietrich (1877). Das Feuerlöschwesen in allen seinen Theilen. Kingdom of Württemberg: Selbst-Verlag des Verfassers. p. 125.
  13. ^ Seitz, Carl (1879). Mitteilungen des Deutschen und Österreichischen Alpenvereins Vol. 05 (1879). Germany/Austria: Deutschen und Österreichischen Alpenvereins. p. 104.
  14. ^ a b c d e "First carabiners for climbing-summary". Retrieved 17 January 2024.
  15. ^ "Carabiner history". Retrieved 17 January 2024.
  16. ^ "Next for Volume 3 (aluminum carabiners, nylon ropes)". Retrieved 17 January 2024.
  17. ^ Baena-Extremera, A.; Granero-Gallegos, A. (2012). "Desarrollo de un modelo de utilidad en descensores para deportes de montaña / Development of a utility model in descender for the mountain sports" (PDF). Revista Internacional de Medicina y Ciencias de la Actividad Física y el Deporte. 12 (48): 681–698. Retrieved 17 January 2024.