Suitable for all underwater metal surfaces, Primocon® is a superb anti-corrosive primer that creates a barrier to reduce pitting. Its an excellent primer for antifouling paint over sanded fiberglass, and wont affect the color of antifouling paint itself. An excellent primer for antifouling paint over sanded fiberglass An 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