[Fast Heating]Upgraded electric heated insoles with built-in carbon fiber heating chip can quickly transfer heat to your feet and gradually warm your whole body. Using electric heated insoles in cold winter helps blood circulation and prevents frostbite, suitable for people suffering from arthritis, poor blood circulation and stiff joints. Heated insoles is a must-have item for winter.[Extra Large Capacity Batteries]Our heated insoles are equipped with two 3500 mAh rechargeable batteries, the battery capacity is more than double of other heated socks available on the market, and the batteries are still light in weight. This ensures that you can use the insoles for a long time to stay warm in cold environments without worrying about running out of power too soon. [High Quality Materials]The insole is made of soft velvet upper and the latest carbon fiber heating material. Folding without deformation, lightweight, flexible, with good cushioning, reusable and washable. The heated insoles has a built-in temperature sensor and control chip, it will automatically stop heating when it reaches a temperature. And provides constant warmth.[Cuttable Size]The heated insoles for men and women can be adjustable to your shoe size, trim the soles for the perfect fit following the size guide. If you have any questions please feel free to contact us ,we will respond within 24 hours and will provide you with the best solution!L,MPolyester