The Sleep Master 4" memory foam mattress topper in king size provides comfort and support to any mattress. Memory foam has pressure relieving benefits and can also help to keep the spine in alignment. Our topper is ideal for back and side sleepers. Memory foam is naturally resistant to dust mites. The Sleep Master 4" memory foam mattress topper includes a quilted, removable and washable cover. All Sleep Master memory foam toppers CertiPUR-US certified and offer a limited 5 year warranty. Our patented compression technology allows for convenient FedEx/UPS delivery. Once you receive your memory foam topper please allow 48 hours for it to fully expand.