Carabiner

A carabiner is a metal loop used as a connector with a sprung swinging gate that allows a rope (or wire or nylong sling[?] or similar) to be inserted or removed. Often used in climbing but also in sailing and industrial rope access work (for example, cleaning the windows of tall buildings). Carabiners used in sport (climbing) tend to be lighter and faster to use then carabiners used in industry. For example, some carabiners used in industry do not have a sprung swinging gate but have a screw shut gate that generally can only be opened and closed using a special tool; using such a carabiner when rock climbing would be unacceptable.

climbing

When sold for use in climbing in Europe carabiners must conform to standard EN 12275:1998 "Mountaineering equipment - Connectors - Safety requirements and test methods" which governs testing protocols, rated strengths, and markings.

There are broadly two sorts of carabiner used in climbing, with some subdivision within that: snapgate carabiners and screwgate carabiners. Snapgate carabiners are the simplest, there is a sprung swinging gate that can be opened to insert or remove a rope. The gate will snap shut under pressure of the spring. Screwgate carabiners are generally the same as snapgate carabiners, but have an additional sleeve around the gate on a screw thread. The sleeve can be rotated along the gate and when it is at one end of the gate the gate cannot be opened (except by unscrewing the sleeve and moving it to the other end of the gate). This provides an additional level of security.