Copper Shield provides antifouling protection on boat bottoms against barnacles, algae, and hydroids in salt and freshwater. Its ablative copolymer base renders a smooth finish with durability and abrasion resistance. Copper Shield releases biocide during 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.