Specification: Output Voltage: DC 5V Output Current: 5.0V / 2100mAh(max) Input Voltage/Current: 5.0V / 2000mAh Battery Capacity: 3.7V/20000mAh Applicable product: intelligent mobile,MP3,MP4,digital cameras etc. Use device: the ordinary mobile power supply Battery type:Poymer lithium battery Input interface: Micro USB Output interface: dual usb output Functional characteristics: portable and convenient,high efficiency of power conversion,long cycle life,economic efficiency Features: High capacity portable battery charger power bank with 20000mAh be charged for iPhone, for Samsung, MP3/4,PSP Android Phones. Built-in 20000mAh high quality rechargeable polymer Li-ion battery Battery indicator display the accurate percentage of power. Dual USB Outputs DC 5V / 2.1A output charge for Mobile Phones,Tablet,Camera,Speaker etc. Ultra high conversion efficiency (> 80%) The certified capacity formula is : output capacity energy=(battery voltage 3.7v battery capacity 20000mah) conversion rate/output voltage 5v. Full charging time(AC power): 10-12 hours. What's in the box 1 x Power Bank