ThermaCell has introduced a pretty darn cool product… Rechargeable Heated Insoles.
They claim that they will last 2,500 hours or 500 uses. They are fully rechargeable and come with a remote to control temperature settings. There are no wires, and no external batteries. Everything is internal. They are pricey… starting at $120, but can you put a price on warm feet in the dead of winter… or stealing your hunting buddy’s remote and totally screwing with him? lol