When you install a crank trigger system, having locked out timing may put a strain on the starter and flywheel. This compact controller provides a retard that automatically retards the timing during cranking to ease the pressure. The MSD Starter Saver measures only 1.5" x 3.5" x 2" and wires into your ignition system with only four wires. It can be programmed to retard the timing 10-Degree or 20-Degree during cranking only. The retard is activated when the engine begins crank ing and the engine reaches over 800 rpm. (If the engine rpm drops below 500 rpm it will activate again.) The Starter Saver receives the trigger signal through an MSD Crank Trigger Pick-Up or the Distributor's magnetic pick-up. This Control has a very accurate pick-up compensation circuit resulting in rock steady timing throughout the entire rpm range of your engine. There is also an LED that illuminates with each trigger signal to confirm operation and the circuitry is completely potted in a polyurethane compound for extreme vibration resistance.