Simmons Beautyrest Waterproof Mattress Pad with "Expand a Grip" polyester Size: Twin - Color: White Simmons Beautyrest Waterproof Mattress Pad with "Expand-a-Grip" that hugs the mattress instead of you. Guaranteed! Unique laminated waterproof barrier provides quiet and durable protection not offered in old pads that used vinyl. Overfilled with Beautyloft polyester fiberfill. Exclusive Expand-a-Grip skirt holds pad firmly to mattresses up to 15" deep. Twin Size. Material Content: Top: 55% Cotton/45% Polyester Back: 100% Polyester with Polyester Laminate Skirt: 100% Polyester with 15" Expand-a-Grip