The 4" or 6" (you choose) BioMedic orthopedic memory foam used in our collection of memory foam dog beds is guaranteed by the manufacturer to NEVER sag, flatten out, get lumpy or break down for the life of your pet! The Crypton fabric used on these beds is easy to clean, dig resistant, and are even waterproof!  These pet beds are a great option for elderly dogs, dogs with arthritis, dogs with hip dysplasia, and large dogs.