Sea Hawk-S-76 Tack Coat Primer is for use on properly prepared steel, aluminum or galvanized steel. S-76 is an anti-corrosive strontium chromate based primer that is specifically designed for underwater metal surfaces including hulls, running gear, and the lower units of outboards and I/O's. It provides an excellent barrier to reduce pitting of the metal from galvanic corrosion. S-76 should be used in conjunction with another primer such as Tuff Stuff prior to applying antifoulant/topcoat.