The Belspring Firm Mattress, from Serta's Perfect Sleeper Elite Collection, has everything you need to get a comfortable nights sleep. Wake up feeling rejuvenated on this all foam mattress featuring slight cushioning, Firm layers of supportive foam. Cool, Gel Infused Memory Foam, just beneath the cover, help pull away heat as the Memory Foam forms to your body, cradling you for a comfortable, supportive feeling. The Serta Base Foam, with a high density foam edge, keeps the mattress shape as it provides optimal surface use. This is a good mattress for a back or side stomach.