AllerZip Smooth Waterproof Bed Bug Proof Zippered Bedding Encasement, Twin XL, (Fits 8 - 13 in. H) 100% Polyester Imported Waterproof: Polyurethane film backing repels liquids like urine and sweat on all six sides Breathable Barrier Fabric: NOT hot to sleep on. Allows body vapor to breathe through pad. 3-sided zipper lock is certified barrier for bed bugs, dust mites and allergens. Easy to Wash and Use: Machine washable in warm or hot water. Tumble dry on medium heat. Fits Twin XL size mattresses 38 x 80 inches, 8 to 13 inch height.