what is a carabiner

A carabiner, also known as a karabiner, is a metal loop with a spring-loaded gate used to quickly and reversibly connect components, most notably in safety-critical systems. The word "carabiner" is a shortened form of Karabinerhaken, a German phrase for a "carbine rifle hook" used by a carbine rifleman to attach his carbine 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 aluminum, with those used in sports being lighter than those used in commercial applications and rope rescue. Carabiners come in different shapes and sizes, with the most common shapes being D-shaped, oval, and pear-shaped. The pear-shaped carabiners are used primarily for belaying and rappelling, but also can be used at anchor points for top roping or multipitch climbing. While carabiners can be found in everyday life, their true functionality is on full display during a variety of outdoor sports.