Variable Fit: Elastic hem and bottom straps fit a wide range of Therm-a-Rest mattresses * Soft and Cozy: Brushed polyester surface is luxurious next-to-skin and protects your mattress * Versatile: Acts as a coupler for another mattress/sheet combo and snaps with our Tech Blanket for additional sleep options * Convenient: Easy to put on and machine washable * Stuff sack included