Patented contour lock system allows the switches to be used as stand alone units or locked together with other switches. The control knob cannot be removed while in the ON or OFF position, but can be removed by switching to an anti-clockwise 45 position. Features tin plated copper studs and nuts. Easy to install with removable side plates on 4 sides for access of up to 1/0 cables plus a rear cover insulating the rear terminals against any short circuits. Rated at 275A continuous, 455A intermittent, 1250A cranking and 48V. Can be recessed or surface mounted. Ignition protected with 3/8" stud size. 2-3/4" x 2-3/4" x 3".