Wool is a natural fiber of animal origin obtained from the coat of sheep. It is naturally curly and wavy, with a very soft and slightly slippery touch before treatment. Most wools are yellowish-white or ivory, but some can be black, brown, gray, or various mixtures. Wool is one of the most naturally stretchable natural fibres. It has a great capacity to retain air and heat, while letting the body breathe, which makes it a great ally for winter.