The circuit breaker locking device is made of industrial grade impact resistant and durable polypropylene and modified nylon The small clamp type circuit breaker lock is suitable for circuitbreaker handles with a width of 0.59 inches or less Keyhole diameter: 0.35 inch When combined with safety padlocks, this universal circuit breaker locking device ensures employee safety and accepts all Master Lock and American Lock safety lock buckles and buckles (padlocks and buckles are sold separately)