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.