Removes stains from grassy marine growth, scum line, and rust. Simple wipe on and rinse off formula makes cleaning your hull quick and easy. Contains no strong acids or harsh chemicals. Will discolor some antifouling bottom paints so take precautions to prevent contact. Much safer to use and less aggressive to your hull then competitive acid based bottom cleaners. Excellent for use on fiberglass, metal and painted surfaces. It's unbelievable.