Bamboo fiber is a cellulose fiber extracted or fabricated from natural bamboo, and possibly other additives, and is made from (or in the case of material fabrication, is) the pulp of bamboo plants. It is usually not made from the fibers of the plant, but is a synthetic viscose made from bamboo cellulose. (In the US, the Federal Trade Commission (FTC) has ruled that unless a yarn is made directly with bamboo fiber — often called “mechanically processed bamboo” — it must be called "rayon" or "rayon made from bamboo". Bamboo is extremely resilient and durable as a fiber. In studies comparing it to cotton and polyester, it is found to have a high breaking tenacity, better moisture-wicking properties, and better moisture absorption. In superseding these other fibers in these various areas, supporters of bamboo fiber products and goods tout it as more eco-friendly than cotton and polyester.