Interlux Primocon Underwater Primer. An anticorrosive primer for underwater metal surfaces (including hulls, running gear, and the lower unis of outboards and I/O's). Provides an excellent barrier to reduce pitting of the metal from galvanic corrosion. Excellent primer for antifouling paint over sanded fiberglass. Won't affect the color of the antifouling paint. Can be used under all International antifoulings or as a barrier/sealer coat over incompatible or unknown antifoulings. Also used to prevent leaching of TBT from an underlying antifouling coating. Can be applied by spray, brush or roller. Suitable for use on aluminum, zinc-galvanized steel, cast iron, fiberglass, lead and steel. Matte finish. Gray. 12 oz aerosol.