Suitable for all underwater metal surfaces, Primocon® is a superb anti-corrosive primer that creates a barrier to reduce pitting. It's an excellent primer for antifouling paint over sanded fiberglass, and won't affect the color of antifouling paint itself. An excellent primer for antifouling paint over sanded fiberglassAn anticorrosive primer for underwater metal surfaces (including hulls, running gear, and the lower units of outboards and I/O's)Reduce pitting of the metal from galvanic corrosion