Serta Perfect Sleeper Hollington Firm Mattress, California King Cool Twist Gel Memory Foam; an exclusive liquid gel-enhanced memory foam designed to help move heat away from your body Serta's Duo Core individually wrapped coils feature a dual-stage coil design to provide consistent comfort and proper back support The Perfect Sleeper is the Only Official Mattress of the National Sleep Foundation, designed with the NSF to help solve 5 common sleep problems 10-year limited warranty Mattress Only, Box spring is purchased separately