What is a 'carabiner' and what safety checks are essential before use?

• A. A device used to suspend loads by attaching to lines.
• B. A decorative hook with no load rating.
• C. A mechanical pulley with no gate.
• D. A metal connector with a spring-loaded gate; check gate operation, locking mechanism (if relevant), and rating.

Answer: (D)

A carabiner is a metal connector used in rigging to attach lines and hardware and transfer a load safely. Before use, you must verify three things: the gate operation, the locking mechanism if it’s a locking type, and the rating. The gate should open and close smoothly and fully, with no stiffness, bent or cracked material, or misalignment that could prevent it from closing and securing the load. If you’re using a locking carabiner, the locking sleeve or mechanism must engage fully so the gate cannot open unintentionally; if it’s non-locking, you still need to ensure it remains closed and that the connection relies on the user’s attention to keep it secured. The rating, usually stamped as a kN value, confirms that the carabiner is strong enough for the load and application; using an un-rated or decorative hook is unsafe, and attempting to load a non-rated item can lead to failure. Decorative hooks have no load rating, and a mechanical pulley with no gate isn’t a carabiner, so they don’t meet the function or safety checks required for a proper carabiner.