MSD 83506 Ready-to-Run Marine Distributor Only three wires to connect for a simple installation High output ignition module produces quick starts, smooth idle and improved mid range performance Accurate and maintenance-free magnetic pick-up never needs adjustment Easily adjust the mechanical advance with the supplied springs and stop bushings to fit your boat's needs Equipped with flame arrestor holes machined into their billet aluminum housings and all units are equipped with weather tight wiring harness