THE ELECTRICAL CIRCUIT FOR THE FUEL PUMP INCORPERATES AN INERTIA FUEL SHUT OFF(ifs) SWITH WHICH WILL STOP FUEL BEING DELIVERED TO THE ENGINE IN THE EVENT OF SUDDEN DECELERATION. It is fitted in the engine compartment, fixed to the bonnet switch bracket on the passenger side = must be reset by pressing rubber top before engine will start. Also fits the Landrover Discovery-Rover 75 MG zt and MGF.