Serta 4-inch Memory Foam Mattress Topper with 2 Memory Foam Pillows --KING SIZE Measures 4 inches thick Density: 3 pounds Originally designed for NASA, this space-age foam cradles your body, reducing pressure points that cause tossing and turning Mattress topper eliminates motion transfer and uncomfortable pressure points Improves circulation while reducing pressure points that can disrupt your sleep Temperature-sensitive foam adjusts to your body temperature so you stay warm