Carabiners (or Karabiners, Krabs, Crabs, Biners!) are a vital piece of safety equipment when climbing. A carabiner is essentially a metal oval loop which can be opened on one side by a gate. They come in many forms but there are two main types, locking (e.g. screwgate), and non-locking (e.g. wire gates). Locking carabiners have a locking feature which prevents the gate opening accidentally, and these are typically used when belaying or at anchor points. Non locking biners are often used in quickdraws or as runners on a route, and can also be used to rack gear.