The heating soleplate has no battery and cannot be stored Electricity or heat. this The insole must be energized to generate heat. you They must be inserted to keep warm. feature: High conversion efficiency, energy saving, average Hours of electricity consumption. Easy to cut into the size you need. Suitable for all kinds of shoes. Make your feet more comfortable and warm. Removable design, practical and clean. USB charger, connect to PC, laptop, charger, let your The feet are warm. Specification: black Material: carbon fiber Function: warm feet Applicable gender: unisex Maximum voltage: 4.5V Heating range: within the shoe range 35 Insole thickness: 4 mm/0.20 inch (approximately) The package includes: 1 pair of X heating insoles 1 X USB data cable