美國KARAM安全帶 Also called "main lock", is used to connect the rope, flat belt and anchors, equipment and other most commonly used connection tools. The safety hook and ring needs to be attached to the lock function. The locking function is divided into two types: hand turn and automatic lock. Hand turn lock is suitable for most environmental applications, but it must be locked immediately after connection. Otherwise, accidents may occur due to accidental equipment collision during operation. Unlocked hooked ring is like the state of the gate opening, its pull (breaking load) is far lower than the state that has been locked. It is divided into two kinds of common type (rotating type) and spring hook (self locking type). The shape is like "D" (rescue, military), "8" shape (Engineering, architecture).