Serta Perfect Sleeper Total Protection Mattress Pad (Twin) Twin: 39 in x 75 in. Face 100% Cotton. Filling/Back/Skirt: 100% Polyester 300 thread count cotton cover, tightly woven to protect against common household allergens. Worry-free stain release protection QuietAssurance waterproof barrier backing for added protection Treated with Microban to inhabit the growth of odor-causing bacteria, laving your mattress pad smelling fresh Fits mattresses up to 20". Easy care. Machine washable.