Copper Shield™ provides antifouling protection against barnacles, algae and hydroids in salt and fresh water on boat bottoms only. Its ablative copolymer base renders a smooth finish with durability and abrasion resistance. Copper Shield™ releases biocide by the constant exposure of new paint film to the water. Copper Shield has universal application over all types of properly prepared bottom paints (except aluminum). For use on fast fiberglass boats, as well as wood and steel hulls.