Basic part of carabiner is its body. Other part of the body is nose and a notch. Carabiner is closed by a gate, ensuring that the rope does not slip out of the carabiner by itself. In most types of carabiners must be the gate closed automatically (not carabiner type A and Q), revolves around the first axis. On the other hand, the purpose of the second axis (sometimes cast together with the gate) is to fit in the notch after closing of the carabiner. This is necessary because the carabiner’s body is flexible and after applying a force slightly expands. So second axis (pin) after a load leans into the notch, fully showing the effect of a closed circuit, which is stronger. The safety lock is used to prevent spontaneous opening of carabiner after its closure. Some types of carabiners must be compulsorily equipped with a safety lock. If the carabiner is fitted with a key-lock system its nose has a different shape. Carabiner with a wire lock does not have axes, first axis is part of a gate and second axis is not necessary, because the nose is hooked directly into the wire.

Carabiner parts

General carabiners requirements: Depending on the type the carabiner must meet load capacity requirements and shall be fitted with mandatory markings.


Each carabiner must show the basic information: Load capacity in longitudinal and cross direction and load capacity with open gate. According to the latest standards must be the strength specified in kN, in older types we can also meet with other units:

kN, 1 kN … 100 kg; daN, 1 daN … 1 kg

A number stating load capacity is actually a breaking strength, when the carabiner snaps (not the value of the regular load). Value should be an integer (in kN) rounded down. According to standard EN 12275 must be the type of carabiners H, K and X marked with a particular letter in a circle.

Carabiner mark

Types of carabiners

Carabiner types and their required minimal static strength. First column specifies type designation according to standard EN 12275. Second column specifies the designation used in mountaineering literature, which is in some cases different (watch for substitution of types D and B). If the carabiner is equipped with auto-lock no requirements are needed for the data marked with an asterisk.

type slang name Longi. open. cross
B „d“ Basic carabiner 20 kN 7kN 7kN
H HMS HMS carabiner 20 kN 6 kN 7 kN
K „k“ Klettersteig carabiner 25 kN 7 kN
A Special piton carabiner 20 kN
D With secured position 20 kN 7 kN
Q maillon With threaded gate 25 kN 10 kN
X „o“ Oval carabiner 18 kN 5 kN 7 kN

Basic carabiner, type B

Sometimes called “D”, “symmetric/asymmetric D”.

Any carabiner that does not meet the requirements for type H, K, D. Gate opening must be at least 15 mm. In the A area must be a space to insert two ropes with diameter of 11 mm without them rubbing the gate.

Suitable for: It is the most versatile carabiner suitable for intermediate points of protection. For self-belay only the type with a safety lock.

Video. Basic climbing carabiner type B. The carabiner is closed by action of a spring. In this case there is an axis (pin) on the upper end of the gate, and at the nose of a carabiner is a notch. The pin will sets into the notch.

More in e-book.

Title Part 2Mountaineering Methodology – Part 2 – Gear and Accessories

ISBN 978-80-87715-08-6

MMPublishing, 2013

Available for download from Apple iTunes (in the Books section).

For example U.S. store – link

Another countries – look on the page Download

See layout.

Another possibility is Google Play. This version is a simplified (as PDF).

Title Part 2 GPMountaineering Methodology – Part 2 – Gear and Accessories

ISBN 978-80-87715-13-0

MMPublishing, 2014

Available for download from Google Play.