The Serta Perfect Sleeper Rolling Knolls Firm Mattress features Sertas Cool Twist Gel Foam and 520 Custom Support Innerspring System. It is designed with a unique set of features to help solve 5 common sleep problems. It helps reduce tossing and turning with Cool Twist Gel Foam as well as encourages proper back support and alignment with Sertas 520 Custom Support Innerspring System. This mattress promotes a balanced sleep temperature with an overall mattress design that helps promote airflow and minimizes impact from partner movement with a premium support system and advanced foams designed for motion isolation. It also resists sagging and edge roll-off with Sertas ComfortLast Construction. This mattress also features a layer of Serta Support Foam, which combines gentle cushioning with extra support for more firmness throughout the mattress.Dimensions: Twin: 39 W x 75 D Twin XL: 39 W x 80 D Full: 54 W x 75 D Queen: 60 W x 80 D King: 76 W x 80 D Cal King: 72 W x 84 D.Serta Perfect Sleeper Warranty.Comfort Level: 2.