Fiber or fibre (see spelling differences; from the French fibre) is a rope or string used as a component of composite materials, or, when matted into sheets, used to make products such as paper, papyrus, or felt. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and Ultra-high-molecular-weight polyethylene.Synthetic fibers can often be produced very cheaply and in large amounts compared to natural fibers, but for clothing natural fibers can give some benefits, such as comfort, over their synthetic counterparts.