Features: Upper material: comfortable,soft fleece 1. Pay attention to materials: Far infrared carbon fiber, through a special process to produce a thickness of only 0.02cm/0.01", soft sheet heating material, its heating evenly, high heat conversion rate, rapid heating, soft and comfortable 2. safe and reliable, the output voltage of the USB interface is only 5V, the output voltage of adapter  is only 6V, and with voltage regulator protection device, the two output voltage is lower than the body safety voltage 36V. 3. energy-saving environmental protection. Power less than 8W, an average of 125 hours consumption of 1 kWh 4. practical. Insole directly placed in shoes, easy to save. Feet separation, flexible and convenient Specifications： Power: USB socket, one end of USB power line is connected with computer USB socket, and the other end is connected with insole Voltage: 5-6V Wash and care: hand washing by water, after washing,should be dry completely then use. Size: 35-36             37-38            39-40               41-42              43-44 23cm/9.06"   24cm/9.45"   25cm/9.84"     26cm/10.24"   27cm/10.63" Specifications: Thermal,Electrically Heated,Hard-Wearing USB heating insoles 3 kinds of heating methods Please select insole in accordance with the size of the inner length of the shoe, The insoles size is CN SIZE 35-36 37-38 39-40 41-42 43-44 Package Included: A pair of insole A USB charging line