Serenia 2-Inch 3-Pound Memory Foam Topper, Cal King by Serenia Sleep. $149.99. 2-Inch 3-Pound Premium Memory Foam Topper will add comfort and support to any sleep surface by contouring to your body and relieving pressure points. The product features an open-cell and cool visco elastic memory foam. Made from the highest quality materials to provide consumers with the best possible product quality and sleep.