Exceptional support and a cool feel are what Serta delivers with its Classic 13"" Elite Extra Firm Mattress. Cool Twist Gel is swirled directly into a breathable foam that promotes airflow and heat dissipation which are both conducive to a deeper sleep. Individually wrapped coils in concert with Serta Support Foam provide contouring and cradling support along with a surface ideal for stomach and back sleepers so you always feel firmly planted.