High density memory foam to provide the best support. Relieves the pain of arthritis, hip dysplasia, joint and muscle stiffness. Memory Foam never loses its shape, providing years of comfort & support. Memory foam has a soft feel that is similar to gel in that it adjusts to your body"s shape and pressure point for maximum resiliency and comfort. Non-allergenic and perfect pad for your pet up to 120 lbs. * The pre-washed fabric cover 37"X27"X4" is luxury Durable 12 oz denim with 100% cotton made which is great for pets with allergy to synthetic fabric. Machine washable and dry-able. The cover completed heavy duty wash cycle for complete softness and clean. Reusable many times. Each 37"X27"X4" denim cover will need 2 yard of fabric that will cost $29++ just the fabric alone compare to large retailer store like Joann. * 2 layers of fabric cover : Inner layer waterproof Taffeta fabric zipper cover with strong industrial stitch to secure the pad. The bed also comes with our durable zipper jean denim fabric cover (outside layer) for easy cleaning and maintain. Only internal zipper cover is waterproof to prevent the water going into the pad under normal use. * New 4" Thick Luxury Comfortable 100% 1 piece Orthopedic Memory Foam pad 37"X27.5" size. Memory foam insert is secured by waterproof internal zipper cover and bombay brown external denim cover. We use the similar memory foam which sold in high end therapeutic mattress store to promote better sleep, healthy joint and long lasting. Additional color/size in Suede brown, Canvas green or extra replacement cover is available here at dogbed4less link on the top for combine shipping discount. Our memory foam and denim cover should last many years under normal use. * Buy 2 discount bundle offer : We will ship 1 additional external denim cover in the total shipment if you buy this bed in quantity of 2 (Total 1 free cover for 2 bed order) and take advantage of combine shipping discount. DogBed4Less pet bed product is more durable and a lot more practical by using the solid full premium memory foam and reusable heavy duty denim cover compare to others poly-fill pillow or multi layer non full memory foam pad. Why spend more money to replace the poly-fill bed regularly while you can get a luxury comfort foam bed that your dog will love and last longer with easy maintain? Additional replacement cover or larger size in XL, XXL or XXXL are always available here by clicking the dogbed4less link next to the title on the top.