A non-toxic, safe alternative to toxic copper based anti-fouling paints. For power, sail, trailered, fiberglass and aluminum boats. A clear, soft moveable barrier surface that can give full season protection in fresh water and intermittent salt-water environments. 450 ml bottle treats a 24' boat and both outdrive. Proven effective in algae and zebra marine growth areas .The thinner it is applied the better it works.