This kind of shoe inserts are made of material for durable and long-term use. With EVA fiber material inside, they are available to be charged by USB cable. Perfect to keep feet in cold weather. Suitable for both men and women to use for all the shoes. Features - Color: Black - Material: fiber, far infrared carbon fiber, USB cable - Size (35-39): 25.00X8.50X0.50cm/9.82X3.34X0.20inch. - Size (40-44): 27.00X9.50X0.50cm/10.61X3.73X0.20inch. - The heatable can keep feet in cold weather. Both men and women can use it. kinds of power supply can be charged, easy to use. It is a wonderful your friend to get rid of the wet winter weather. - Wide range of application, all kinds of shoes can be used. You can freely cut the size according to the length of the foot. - Get rid of the wet winter weather. Work in the cold outdoors or in the . - The materials used are waterproof. Can be washed directly without affecting the effect of use. You can also clean with a brush. Package list: 1 pair x heating 1 x USB cable