Wool is classed as follows: fine, usually short-staple wool of Merino fineness and including Delaine Merino, combable fibers 2 in. (5.1 cm) or more in length; medium, or mutton, 2 1/2 to 6 in. (6.4-15.2 cm) long, e.g., Cheviot and Southdown; long-staple, 10 to 15 in. (25.4-38.1 cm) long, loosely crimped, e.g., the Lincoln and the Cotswold; and carpet, 1 to 15 in. (2.5-38.1 cm) long, strong, coarse, and usually blended for uniformity. For industrial purposes the fiber of the camel , Angora goat (see mohair ), Kashmir goat (cashmere), llama, alpaca, and vicuña is classed as wool.

Sheep Wool : Sheep are sheared with mechanical clippers. The fleece thus recovered is classed as lamb's wool, or first clip; hog wool, clipped from sheep 12 to 14 months old; wether wool, from older animals; taglocks, the ragged, discolored portion; and pulled wool, usually weakened when recovered by sweating or chemical processes from sheep slaughtered for mutton.

Acrylic : Acrylic fiber is the generic name of manmade fibers derived from acrylic resins (minimum of 85% acrylonitrile). Acrylonitrile is also a key raw material for the manufacture of modacrylic (new window), an important flame retardant fiber used in protective clothing,substance is any long-chain synthetic polymer composed of at least 85% by weight of acrylontrile units, —[CH2—CHCN]n—. More about acrylonitrile.

Major trademarks: Cashmilon, Dralon, and Dolanit

Acrylic properties:

• Shape retention
• Resists aging
• Excellent chemical, heat and UV light resistance
• Superior moisture management or wickability
• Quick drying time (75% faster than cotton)
• High electrical resistance
• Takes color easily
• Will not melt
• Odor and mildew resistant
• Low moisture regain (1.5 - 2.0%)
• The most wool-like of the synthetic fibers

The lowly sock is an apt metaphor for arcylic's benefits. The athlete and the foot soldier prefer acrylic socks because they retain their shape, not drooping or bunching up in the shoe or boot. They also wear well, and so on down the list of benefits.

Nylon : It is the most popular and represents two-thirds of the pile fibers used in the United States. Wear-resistant, resilient, withstands the weight and movement of furniture, and provides brilliant color. Ability to conceal and resist soils and stains. Generally good for all traffic areas. Solution-dyed nylon is colorfast because color is added in the fiber production.