Protection for a black car

[JBs]

Well it's heating up over here in socal, and i have a couple customers that come to me every week for a wash, and the ones with black cars that live in the heat (sun valley etc) don't have any wax left after the first week!

what can i use to provide good protection for their cars when it starts to get hot?

Feed back please

[D]

WG DGS. Got some on the shelf, just havent used it yet.