Spandex generally use bare wire with nylon or other fibers (cotton, wool, hemp, silk, chemical fiber, etc.) made with the yarn after the warp, weft, weaving weaving and other processing equipment. Spandex bare yarn elongation as large sliding performance is not good, so multi-purpose Covered Yarn, yarn, weaving the form of joint stock yarn system. The spandex yarn in the lower levels (2% ~ 25%) will be able to give full play to the role of spandex for flexibility.