Roving and yarn are fibers twisted into a feedstock for weaving cloth or reinforcing composites. Yarns are long, continuous lengths of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, and rope making. Yarns can be made from any number of synthetic or natural fibers. Examples of natural fibers include wool, angora, cotton, silk, linen, bamboo, hemp, and soy. Commercial yarns are often made from synthetic fibers or a combination of natural and synthetic fibers. Very thin yarns are referred to as threads. Roving is a condensed sliver, which has been drafted, twisted, and wound on a roving bobbin. Specialized roving and yarn types are also available.