Rest Assure Terry Cotton 100% Waterproof Mattress Encasement Cotton Protects against bedbugs, dust, dust mites, allergens, and bacteria. Completely encases the mattress for added protection and has an internal protective flap and a velcro closure cover with a zipper for protection. Fits mattresses 8"-24" in height Made with soft terry cotton fabric for a soft sleeping surface and with a breathable polyurethane backing for a cool and comfortable feeling. 100% waterproof. Will repel spills, accidents, and stains