Lycra (LYCRA) is a spandex fiber, a man-made elastic fiber exclusively invented and produced by the DuPont companyin the United States. It mainly has the following advantages: 1. Very elasticand not easy to deform: Lycra has excellent stretchability. It can be easilyand freely stretched 4 to 7 times, and can quickly return to the originallength after the external force is released. Adding this lycra fiber to sockscan be more durable and support long-term wear without losing elasticity. 2.Can be mixed with any fabric: Lycra is a "friendly" fiber that can bemixed with man-made or natural fibers, but not alone. It does not change theappearance of the fabric, it is an invisible fiber, and a small amount of itcan greatly improve the performance of the fabric. 3. Comfortable and close tothe body: Lycra can be closely attached to the surface of the human bodywithout any binding force on the human body.