The Longacre battery master switches are available in two formats.Panel Dimensions: 3 3/8" x 3 5/8"Body Diameter (At largest point): 2.647"Body Depth (From end of threads to lock washer): 2.980"Overall Depth: 4.216"A 2 terminal switch is available, which acts as a battery isolation switch that will ensure complete electrical isolation of the vehicle when it is switched off, so it cannot be re-started. A 4 terminal battery master cut out switch will ensure complete electrical shutdown on a running competition car when operated. It also prevents damage to the alternator diode and prevents engine run on when operated. All switches feature a bright red handle that is easy to find in an emergency and a matching mounting panel. All the switches will work on 6, 12 or 24 volt systems.