420 mAh output at 5 volts. This is a replacement or spare USB charger for your eGo (C, T, W, and Twist) batteries. Plugs into any USB port for charging via computer or plugs into the wall adapter (sold separately) to allow for wall charging. Green light indicates no battery attached or battery attached is fully charged. Red light indicates a charge in progress. Approximate charging time for batteries is 2-3 hours.