The M12 Power Source, Compatible With All M12 Battery Packs, Features A 2.1 Amp Powered Usb Port That Charges Tablets, Smart Phones, MP3 Players, and Other Portable Electronic Devices. This Smart-Charge Port Identifies The Electronic Device Being Charged; Delivering Fast, Safe Charging. The Adapter Features An On-Board Fuel Gauge, and Is Compatible With All M12 Heated Gear, Providing Up to 6 Hours Of Continuous Heat On A Single Charge. (Battery Sold Separately).