Circuit Breaker Lockout requires no tools to tighten the device onto the breaker. A thumbscrew allows the device to be installed quickly and easily. The 480/600V breaker fits circuit breakers up to 2 1/4″ wide and 7/8″ thick. The lockout measures 2-3/4″H, 2-5/8”L, 3-3/4″W and accommodates one padlock, with shackles up to 9/32″’. The device is made from durable plastic (polypropylene) and nylon.