BARRIERSHIELD™ Barrier Coat Primer is the perfect primer for applying bottom paint over underwater metals or unknown antifoulings.  It provides an adhesion layer for new paint and the required electrical barrier to prevent galvanic corrosion from occuring between a copper-based paint and the vessel's underlying metal (e.g., trim tabs, struts, seacocks etc.), ensuring maximum life and effectiveness of the antifouling paint.  Covers 100 square feet per quart.  Two coats recommended.