Note:This heating insole does not have a battery, and it cannot store electricity or heat. The insole needs to be powered on to generate heat. It can be cooled when the power is turned off. Comfortable Materials: Thermal soles with EVA elastic fiber sole material + Far-infrared carbon fiber heated material,which has uniform heat generation, high heat conversion efficiency, rapid heat generation and softness. Don't include battery and charger. 3 Heating Modes: Adapter plug-in, USB link computer, power bank heating (power bank power 5V/2A or more)Put the Heating Insole in your shoes and connect them to the power supply to enjoy the warmth. Stable heating, guaranteed safety, perfect to keep your feet warm in winter. Fast Warming: These USB Heating Insole with a thin design and a thickness of only 4 mm. A high-temperature heating of 40 to 50 degrees not only protects your feet from cold winters, but also promotes blood circulation. Waterproof: Washable and reusable. The materials used are waterproof. Can be washed directly without affecting the effect of use. You can also clean with a brush (not for machine washing). Tips: Must be completely dry before use and keep the USB port away from the water when connecting the USB power. Free Size Adjustment: Electric heated foot warmer insole can be tailored to your size. According to the easy cutting route you can cut the soles for your own shoes. Suitable for most shoes. It is recommended to buy two pairs of heated insoles for alternating use.