Stretchable fabrics, also known as elastics, are fabrics that can be stretched and return to their original shape. They are usually made from synthetic fibers such as spandex, polyester, or nylon. These fabrics are often used in clothing, swimwear, and lingerie because they provide a comfortable fit and are easy to care for. Elastics are also used in medical applications such as braces, bandages, and prosthetics.