MSD Ignition 8644 7.25" Crank Trigger Wheel Kit Flying Magnet for BB Ford

Most crank triggers have a wheel, with steel studs sticking out, bolted to the harmonic balancer. As the crankshaft turns, the studs pass by a stationary magnetic pick-up, triggering the ignition. This pick-up can be triggered by other bolts, debris, or even vibrations which will cause a loss of power or engine damage. The MSD Flying Magnet Crank Trigger uses four magnets secured in the aluminum trigger wheel that pass by a stationary non-magnetic pick-up to trigger the ignition. This "flying magnet" design produces accurate trigger signals and the non-magnetic pick-up cannot be falsely triggered.