The M18 Power Source, compatible with all M18 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 guage, and is compatible with all M12 Heated Jackets and Heated Hand Warmers, providing up to 18 hours of continuous heat on a single charge.