It fits over the device toggle switch and clamps in place by tightening the thumbscrew (no tools required); once tight, pull the cover over the thumbscrew and insert a safety lock with a shackle up to 7.5mm diameter.
Made of durable plastic, it works with single-pole and triple-pole breakers. With the base plate removed, it fits onto larger MCBs as well as some makes of cooker / 20A DP Switches.
It will fit to a toggle switch up to 11mm thick & 16mm wide.
