Car bras are a topic that are discussed frequently at the local Corvette club. If used correctly they can prevent highway stone chips, but they seem to do more damage if left on for daily driving. When wet, the exposed fibers around the ends collect grit that will rub on the paint causing rub marks. They are also slow to dry. When I used to judge car shows, I saw several cars with these marks. Bras may be good for a road trip, but take it off for daily driving and wash it between uses. If you want chip protection, look into the 3M film protector.