they dont stop stone chips, but it gives an extra layer in the clear so that its more likely that the clear will chip rather than the paint itself, they do offer some scratch resistance but that is more like swirls/grit protection rather than being keyed. i'm mainly going at it for the sun protection, stone chips can be touched up, sun damaged paint is a respray lol
exactly melb nut the products have improved significantly over the years I have a friend with a 458 ferrari and it looks superb so hard to see you don't even know its there