Oztent Rivergum Self Inflating King Single Air MattressA Very Comfortable Sleep The Rivergum Self Inflating Mattress' excellent insulation is a result of combining open cell foam, air tight vinyl, and velour backing. The open cell foam sucks in air when the valves are open and before you know it you have a thick, comfortable mattress to sleep on. They fit perfectly in all of our tents and even fit on the top of stretchers. FEATURES Insulation loss prevention with CFC FREE, extra thick open cell foam Slip