A hard antifouling with dual biocide, perfect for both power and sailboats with fiberglass, wood, or steel hulls. 70% cuprous-oxide means unprecedented resistance to barnacles, algae, slime, and other marine fouling organisms. Can be applied over most hard antifouling coatings. Old, soft antifouling coatings must be removed before applying. Use 120T10 thinner for brushing or 121T8 for spraying.