Copper Shield Hard™ 35 provides antifouling protection against barnacles, algae and hydroids in salt and fresh water on boat bottoms only. Its modified epoxy base renders a smooth finish with durability and abrasion resistance. Copper Shield Hard™ 35 releases biocide by the exposure of new paint film to the water. Copper Shield Hard™ 35 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.