Clamp-on breaker lockout is widely used and can be easily installed with a proprietary finger wheel design screw – no screwdriver required; The included non-slip nail can be removed to extend the scope of application for circuit breakers. Generally used for locking single-pole /1P molded case circuit breaker, according to the size of the circuit breaker handle selection, there are three specifications: large, medium and small; Both small and medium sizes come with a base.