Carabiners, also known as Karabiners or Krabs, are opening metal links which can connect ropes or slings to each other, or to pulleys or other equipment.

They are of critical importance in rope systems including:

• lifelining with a dynamic rope to arrest a fall in rock and ice climbing or with electron ladders in caves
• ascent and descent on static rope in caving (SRT) or canyoning

When used as part of a safety system, locking carabiners are often preferred - these secure the gate in the closed position to prevent accidental opening. An open carabiner is much weaker (typically less than ⅓ of its full strength when closed).

Light-weight (always non-locking) carabiners are also available, for racking gear to a harness or anchor point. These must not be used where they might have to hold a fall, or even a body weight.