Mainstays 8" Memory Foam Mattress, Multiple Sizes: Memory foam reacts to body heat and pressure and molds to the body's natural shape, thus evenly distributing body weight and alleviating unnecessary pressure on jointsIt returns to its original shape once you remove the pressureReduces back pain and increases circulation for better sleep8" mattress thicknessSoft cover is made of PolyesterMeets federal flammability standard 16 CFR 1633Mattress is shipped compressed, rolled and vacuum sealedAllow 48 hours for the bedding to expand to its proper size and shapeBed frames sold separately, see our assortment of bed framesAvailable in twin, full and queen sizesTwin mattress dimensions: 75"L x 39"W x 8"HFull mattress dimensions: 75"L x 54"W x 8"HQueen mattress dimensions: 80"L x 60"W x 8"HTwin mattress box dimensions: 40.5"L x 11"W x 11"HFull mattress box dimensions: 56"L x 12"W x 12"HQueen mattress box dimensions: 62.5"L x 12"W x 12"HBeds sold separately. See our assortment of beds. Bed frames sold separately. See our assortment of bed frames. Great for platform beds. Requires foundation or box spring with standard bed frames. Foundations sold separately. See our assortment of foundations.