Marine environments place strict demands on each component of the ignition system. The combination of splashing water, showrooms, full throttle acceleration and hard vibrations all take their toll. The MSD Pro-Billet distributor is the strongest and most accurate for your boat. The housing is CNC machined from a piece of 6061-T6 aluminum creating a housing with no porosity. Each distributor uses MSD magnetic contacts with stop to activate ignition control. Mounted just above the contacts is a mechanical advancement group that is easy to adjust so you can dial in a ignition curve to match the application of your boat (except PN 8366). For marine use, distributor protection is bolted to the aluminum base. There are two baffle holes with brass shields machined in the distributor base to prevent ignition of gas fumes that can accumulate in the engine compartment