Product Description Features: Waterproof DesignWashable and reusable. The materials we use are waterproof. Can be washed directly without affecting the use effect. You can also clean with a brush (not for machine washing). It needs to be completely dry before use. (it is recommended to buy two pairs of insoles and replace them in turn to extend the use time of insoles) 3 Heating MethodsUSB interface heating, power adapter heating, mobile power bank heating, large heating surface, even heat distribution, which can be heated to about 50. Safe and EfficientStable heating, safe and reliable. Carbon fiber electric heating wire heats the insole for uniform heating, high heat transfer efficiency, fast heating speed, soft and comfortable, and is an ideal health heating material. Free Size AdjustmentElectric 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, 35 to 44 yards, cut according to the dotted line according to the number of yards you need. Great for WinterThe heated insole is suitable for running, fishing, hiking, skiing, motorcycle riding, hunting, mountain climbing, running, sledding and other outdoor sports in harsh winter, they can also promote blood circulation and other health effects and reduce the stiffness of outdoor sports Specifications: Material: Carbon Fiber Color: Black Power Supply: USB powered Voltage:5V/2A Heating Range: 35 yard line range Temperature: About 50 degrees at room temperature Thickness: 4mm /0.15inch(appr.) 2 yards: Small size: 35-40 size or large size: 41-46 size Package Included: 2 x Heated Insoles 1 x USB cable