King Size CertipurUS Memory Foam Mattress Ultra CoolingSleep cooler, wake refreshed. The King Size CertipurUS Memory Foam Mattress UltraCooling blends cooling gel infused memory foam with a breathable open cell structure to keep you comfortable all night, even in warm environments. Cooling technology Gel infused memory foam plus a ventilated open cell design improves airflow and reduces heat retention for a cooler sleep surface. Pressure relief & spinal alignment Open cell memory foam paired with bamboo