ive used it on rock chipped up fender wells back when i had my s10 on air ride. since it was so low it would throw rocks right into em baring it to bare metal and it would rust. so i sanded it off, prepped, and applied it. with my truck being black it actually was not visible unless you knew it was there and decided to get down and under to look at it. but in short its tough. didnt chip off for the rest 8,000 miles i put on it and didnt rust or fade in that time.