Serta Perfect Sleeper Nurture Night 13.5" Medium Mattress. This mattress is very comfortable. The Cool Twist Gel Memory foam supports my body in all the right places and keeps me cool all night. I’m no longer waking up with hip pain. Mattress is made with high quality materials and is built to last. The Serta Perfect Sleeper Nurture Nights delivers as promised. I love this mattress!