Serta® Perfect Sleeper® Medium 13 delivers perfect sleep, night after night. Featuring our Q4„¢ Support System, 860 density 4-in-1 coils that are perfectly linked for even weight distribution and long-lasting support with BestEdge„¢ Foam Encasement for stability. Our unique 5 Zoned Comfort features alternating firm and plush areas and is designed to hug the curves of your back and body for perfect support. PillowSoft® Aire foam offers enhanced cushioning for exceptional comfort while promoting airflow. A layer of CoolTwist„¢ Gel Foam offers enhanced airflow, heat dissipation, and contouring comfort. Stay cool and comfortable with breathable wool, plus CoolFeel® Fabric engineered with cooling performance technologies. The Serta® Perfect Sleeper® with Q4„¢ Support System helps relieve aches and back pain with consistent comfort, reduced pressure, and long-lasting support at a great value”for perfect sleep, night after night.