Natura's Washable Wool Fitted Mattress pad has a 3/4 inch layer of pure wool fill quilted inside a 100% cotton sateen cover. The cover has an elastic skirt to secure the pad snugly around mattress. The wool helps to maintain a regulated body temperature, it helps to wick moisture away from body, resists dust mites, mold and mildew. It is ideal for every season and climate. The Fitted Mattress Pad is filled with 10oz/yd NaturaWool creating a moisture-free, temperature controlled barrier that repels common allergens and machine washable! The cotton sateen cover has a fully elasticized cotton percale skirt that fits mattresses up to 15" deep. No flame retardants are used in this product.