Featuring a 3 zoned coil design, the Serta Perfect Sleeper Cobalt Calm Medium Pillowtop mattress offers pressure relief and support where you need it, with a Cool Twist® Gel Memory Foam that contours to your body—with upgrades available with more cooling layers and support. Cool Twist® Gel Foam Cooling gel is swirled directly into a breathable foam designed to promote airflow and heat dissipation. Cool Twist® Gel Memory Foam This unique design features cooling gel swirled into premium memory foam. This breathable memory foam helps enhance airflow and heat dissipation for a feeling that can only be described as a cool, contouring type of comfort. PillowSoft® Aire Soft foam provides enhanced cushioning for exceptional comfort and promotes airflow through its unique, gently rippling design. 3 Zoned Coil Design This 850-coil density system offers three support zones with targeted support for your lower back and hips and cradled comfort everywhere else. Anti-Microbial Technology Our anti-microbial mattress technology will keep your mattress fresh and clean from odor-causing bacteria. QuiltLoft® Memory Foam This conforming quilt-layer foam hugs your body for additional comfort at the surface of your mattress.