Power up the warmth where you need it most with the ActionHeat 3.7V 2200maH Rechargeable Battery Kit for Socks. Designed for use with ActionHeat 3.7V and AA Heated Socks (not included), these rechargeable kits feature a lithium-polymer core to keep long-lasting heat flowing on a full charge. Buy a spare kit and double the heating time for long days spent outdoors. It's the perfect solution for cold-weather work, hunting, hiking, tailgating and attending sporting events. The slim size slides right in the battery pocket at the top of the socks. Batteries fully charge in 3 to 4 hours. Disconnect batteries when not in use and remove before washing socks. Kit includes two 3.7V 2200maH rechargeable batteries and 1 wire charger. Imported.Manufacturer model #: AH-3V-2200-KIT. Designed for use with ActionHeat 3.7V and AA Heated Socks Lithium-polymer core keeps long-lasting heat flowing Buy a spare kit and double the heating time for long days outdoors Great for cold-weather work, hunting, hiking, tailgating and attending sports Slim size slides in the battery pocket at the top of the socks Batteries fully charge in 3 to 4 hours Includes two 3.7V 2200maH rechargeable batteries and 1 wire charger