ULTCOVER Waterproof 600D Polyester Square Hot Tub Cover Outdoor SPA Covers 95 x 95 inch, BlackGeneral to fit hot tub size up to 95(L)x 95(W). NOTE: This cover can not be used by itself without an insulated hard cover under it. Made of 600D polyester canvas complex with waterproof backing. Tough enough to keep rain, hail, snow, dust, leaves and bird droppings away. Well made structured air vents at two sides keep ventilation, prevent the cover from being blown away, also keep your furniture dry and in good condition. Heavy duty elastic cords