A killswitch is an ignition breaker that is used mainly for racing. It is an emergency stop switch that in case of a fall or accident immediately cuts the ignition, the engine dies off, so that no further damage can occur. ... Some racing regulations even require the use of a killswitch. It can also be used as a kind of immobilizer. We carry efficient killswitch ignition breakers from Stage6 and MXS Racing for the wrist. In this category you will also find classic ignition breakers, i.e. simple on / off switches.