USB heating insole, electric heating foot warmer, rechargeable heating, washable 1. Far-infrared carbon fiber, through a special process to produce a soft sheet-like heating material with a thickness of only 0.02cm, which has uniform heating, high heat conversion rate, rapid heating, soft and comfortable. 2. High conversion efficiency, energy saving, an average of one kilowatt-hour. 3. Easy to cut to the size you need. 4. Suitable for various shoe types. 5. Make your feet more comfortable and warm. 6. Detachable design for easy cleaning. 7. USB charger, connect PC, laptop, charger, keep your feet warm indoors. Important Note: If you use a power bank, the output power must be 5V/2A. The USB heated insole has 3 heating methods: 1. USB interface heating (including USB cable) 2. Power adapter heating (including adapter) 3. Charging treasure heating (without charging treasure) Specification: Material: Heating Material: Carbon Fiber Upper Material: Elastic Fiber Colour: Black Washing and maintenance: hand wash with water, after washing, it should be completely dried before use Thickness: 4mm Heating temperature: approx. 50 Size 35-40, Length: 22.5-24.5cm Size 41-46, Length: 25-27cm Package Included: 1 x pair of heated insoles 1 x USB data cable (battery not included) 1x adapter notes: 1. There is a 2-3% difference based on manual measurement. 2. Please note that due to light and screen, slight color difference is acceptable.