The Sealy memory foam Mattress in a box collection offers 3 thicknesses, each featuring a unique combination of memory foam layers that promote airflow and provide conforming comfort, pressure relief, and support, keeping you comfortable throughout the night. Featured is premium high-density memory foam, which conforms to your body and provides pressure relief. Mattresses offer responsive comfort foam, which reduces motion transfer with the right amount of responsiveness to prevent sinking. The foam Mattress in a box brings the comfort of straight to your door. Place your mattress on your bed, remove the packaging, and allow time for the bed to decompress and expand to its lofty, comfortable shape.