Polyester fleece is a soft, fuzzy fabric used for sweaters, sweat shirts, jackets, mittens, hats, blankets, and in any other applications where a warm, wool-like material is needed. It is a two-sided pile material, meaning that both the front and back surface of the fabric sprouts a layer of cut fibers, similar to corduroy or velvet. Polyester fleece is an extremely durable fabric that not only holds in warmth but resists moisture and dries quickly. Unlike many other synthetic woolly textiles, polyester fleece does not pill-bunch up into little balls-after extended use. It became popular for out-door gear in the early 1990s, because back-packers and hikers found it lighter weight and warmer than wool. It is increasingly popular as a fashion fabric, and has found a host of more specialized uses. Polyester fleece has been used to make underwear for astronauts, in deep-sea diving suits, and as ear-warmers for winter-born calves.