Unique to the Contour Battery Master Switch is the patented contour lock system which allows the switches to be used as stand alone units or locked together with other switches. The 701RV features a control knob which cannot be removed while in the ON or OFF position, but it can be removed by switching to an anti-clockwise 45 deg position. The 701RV also features 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.