Incorporates a secondary switch to isolate the ignition circuit, a vital safety factor in competition use. At the same time the main electrical circuit is grounded (earthed) through a 3 ohm 11 watt resistor to prevent surge and protect the alternator circuit. A simple and effective anti-theft device for cars, lorries, boats and agricultural vehicles. Can be flush mounted to a panel (max 12mm thick). Requires a mounting hole 22mm diameter and 2 x 6.5mm diameter bolt fixing holes 37mm apart.