Knit 11" KING ULTRA-FIRM SPRING MATTRESS: Provides the perfect balance of luxurious comfort and optimal support with an ultra-firm gel mattress feel to help you get the blissful night of sleep you deserve LAYERS OF COMFORT: SealyCool Air Gel Foam paired with the fabric-encased coils delivers a flexible, breathable comfort, conforming support, and reduced motion transfer SUPPORT WHERE YOU NEED IT: Sealy was the first ever to reinforce the center third area of the mattress which targets the heaviest part of your body, allowing you to stay well-supported while you sleep DURABLE COIL SYSTEM: Reinforces the edge of the mattress to offer more sleeping space while preventing sagging over time and increasing flexibility when paired with an adjustable base COOLING PROTECTIVE COVER: Durable, soft knit fabric cover features moisture-wicking to help you stay cool and cozy and antibacterial Surface-Guard Technology for superior protection