http://justhomemedical.com/drive-prem... The Drive Premium Guard Gel/Foam Overlay is ideal for the prevention and treatment of pressure sores. The gel mattress features 15 full-length "head to toe" gel bladders that minimize "bottoming out" and "pitting", in addition to cover the entire user contact area. Bladders contain an aqueous non-toxic gel and polystyrene beads. This gel overlay also features convoluted foam topper, which improves user comfort and air circulation, and designated head and foot sections. The vinyl base is stain resistant and waterproof; and the urethane coated nylon cover is water resistant and vapor permeable. The gel pad attaches securely to the mattress using four elastic corner straps. The standard pad has a weight capacity of 300 lbs.; the bariatric bed pad supports up to 500 lbs. This pressure prevention overlay is an excellent way to alleviate pressure points and prevent bed sores. This overlay features full length gel bladders that are soft, yet will still retain their form even after prolonged use. The foam topper improves pressure distribution while still allowing air to circulate to keep the overlay breathable. Plus the 4 elastic straps will keep the overlay firmly in place, even for active sleepers. And for better durability the nylon cover is urethane coated to make it water resistant yet breathable.