USB Charging Heated Insoles : The heated insoles adopt new heating technology, made oft and comfortable EVA stretch material, with good cushioning, portable Light, the heater is comfortable with USB interface is used for heating via the USB cable, large heating surface, even heat distribution, temperature reach up to 42 C/108 .Cleanable & Charging Use : This usb insoles material has a waterproof effect, is washable and reuseable, you can wash it via brush, not for machine washing, it should be noted that it needs to be dried after washing, and must be completely dried before use.Wide Range of Uses & Best Gift The heated shoe insoles keep your feet warm in cold winter, the temperature will reach up to 42 C/108 , so no matter where you go, you can keep you warm suitable for skiing and outdoor sports, other sports, camping,chores,hunting, hiking,fishing etc, is best christmas gift.