This is a portable rechargeable heated insoles. Rechargeable lithium ion polymer batteries are mounted to your calf via velcro tape. These can be charged via power bank or worldwide ac adapter
High capacity batteries offer 5-6 continuous hours of run time with fully rechargeable Batteries. Warming time is varies in different environment. The temperature will reach up to 120 °F to warm cold feet in winter without too hot to sweat.