Sleep Better Isotonic Iso Cool Total Body Comfort Topper with Outlast Cover, King cotton Isotonic and Iso-Cool are Registered in U.S. Patent and Trademark Office 3-inch, 2-1/2-pound density, 100-percent visco-elastic memory foam topper 300tc, 100-percent cotton cover with outlast adaptive comfort material 17-inch tightgrip skirt fits up to 21-inch Hypoallergenic and cover is machine washable