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.