Crane Cams has developed an industry first with their fully electronic distributor that allows you to choose from 36 pre-programmed advance curves with the simple twist of a dial. No springs or weights mean no hassles or maintenance! It uses an optical trigger with a stainless steel trigger disc for precise firing and reliability. The magnetic trigger plug will work with Crane ignition systems. Other features are a billet 6061-T6 aluminum housin with quality upper and lower bearings. Fully urethane sealed from dirt, vibration and moisture. Chevy models feature a slip collar. Precision MAP sensor, locked-out timing and zero vacuum required for advance curve system. Accurate to +/-0.5° at all RPM