Feature:Built-in rechargeable 2000 mAh lithium battery provides 4-7 hours of use time.Suitable for outdoor enthusiasts and outdoor workers.Heating elements made of carbon fiber produce consistent heat to keep you warm in cold weather.Size-adjustable design insole can be used for almost any shoe, boot.The insole of high-resilient foam and velvet fabric material is thick enough to provide a comfortable experience.Specification:Name: heating thermal insoleConditions: NewColour: BlackGender: MenMaterial: 95% cotton + 5% spandex, carbon fiber strandNotes:The product does not contain mobile powerAlways need to move the power supply to the heat (recommended 5V2A mobile power)Package Includes:1 Pair Heated InsolesAt last:1. Due to the difference of light and screen, the color of the product may be slightly different from the picture.2. Due to manual measurement, please allow an error of 2-5 cm.We will use the best products and services to help you.We hope that every customer will be happy every day ^ _ ^