Serta Roswell Plush Mattress Set, California King The Serta perfect sleeper is the only official mattress of the national sleep foundation (NSF), designed to help address 5 common sleep problems Ever cool memory foam: the unique open-cell structure of Serta's exclusive and breakthrough foam makes it more breathable, to dissipate heat away Custom support system: a durable, yet flexible all-foam support system is engineered to provide the right amount of support across the entire body Mattress Set includes Serta Perfect Sleeper 9" Stable-Base Foundation