"This Clamp On Circuit Breaker Lockout device from RS is extremely versatile and easy to install. Its patented thumbscrew design means no tools or screwdrivers are required for installation - simply tighten the lockout device onto the switch tongue and pull the cover over. Then use a lockout padlock (not included) to lock the cover to prevent the clamp from being loosened.Type = Clamp-On Breaker LockoutNumber of Locks = 1Lock Shackle Maximum Diameter = 7mm"