1450mAh lithium ion battery doubles the battery life of the iPhone * Front-facing LED indicators provide power status of case in 10% increments * Device and case charge/sync simultaneously - OtterBox iON Intelligence app automatically transfers power from case to device upon 20% batter alert * Eliminating guesswork, the OtterBox iON Intelligence app clearly displays power status for case and device separately * Included 4.2 mm Micro USB cable enables faster charging speeds