Ideal for use on aluminum, Trilux 33 is also excellent for use on fiberglass, wood, and steel. Biolux blocks slime. Two biocides working together increase antifouling properties. Trilux 33 should be used with thinner 433 (sold separately). Two biocides for more antifouling protection | Interlux Trilux 33 Antifouling Paint, Gallon in Black