I have a bottle of some Turtle Wax product, I can't recall the exact name. But they replaced it with something else. Pretty much any protectant that blocks UV and treats the rubber will work. But if the seals are already drying out, then the protectant can't do much to help.
2013 Jayco Jayfeather X20 E, 2008 GMC Sierra 1500 Crew Cab Z71 SLE