ISound BP-420 Rechargeable 10,400mAh Capacity Battery with Dual USB Output Ports + Built-in Charge and Output Cables On Board 47 Hours of additional talk time or up to 300 hours of power depending on use. Dual USB output ports, one for 2.4Amp output and the other for 1 Amp output for full speed charging of virtually any USB powered device Built-in charge and output cables for convenience, plus space for optional micro to Lightning adapter on back of battery (sold separately). LED charge indicators indicate level of charge on battery  (always know when to recharge) and built-in flashlight for convenience. Comes with A/C adapter for convenient recharge virtually anywhere. Fully certified with overheat and overcharge circuits to guarantee safe use.