One example is to connect the GMR, which stands for Giant Magneto Resistive, to a diesel injector current wire. This will produce a signal that can be used to trigger a tachometer or shift light! Another example is on late-model engine equipped with a coil-on-plug ignition system. One of the coil's primary current wires is simply routed into the pickup clip and GMR converts this pulsing into a 12 volt signal for a shift light! Just think of the things you can easily accomplish with our GMR Pickup! This little device simply attaches, with no splicing or cutting, to a current carrying wire and turns that information into a 12 volt rpm signal. This signal can be used to activate a shift light, rpm activation switch or a tachometer.