One of my fog lights was destroyed by a rock and I replaced them with new Depo projector fogs. To prevent it from happening again, I decided to try out a precut Lamin-X film kit. It has two precut sheets of urethane film that adhere to the lens of the fog light. This film prevents all but the largest of rocks from chipping and cracking the glass lens. The film comes in a 20 mil or 40 mil thick size. I opted to go for the 40 mil. It is actually quite thick and maybe 20 mil would have been just fine. In any case, it would take a huge rock to take out the lens again. I ordered it from www.lamin-x.com. I have to admit that is a little pricey for the amount of film you get (2 round pieces for around 17 shipped). It does beat a broken fog light though.