Our 4400mAh power bank / portable dual channel charger is equipped with dual slots for charging up to two GoPro AHDBT-401 batteries simultaneously, power switch, three display lights (one for power and two for charging status), and mini USB and USB ports. To charge the batteries, insert them into the slots and press the power switch two times (first - to turn on the charger and second - to start charging). If you would like to take the battery out, press the switch once for a few seconds to stop charging. The charging lights will be red and flashing, when the battery power is below 30%, blue and flashing - when the power is between 30 and 70%, and green and flashing - when the power is above 70%. The lights will be green and stop flashing when the battery is fully charged. To re-charge the power bank, just connect it to a regular USB wall adapter using the mini USB cable. 

Specifications:

Input: 5V 1A
USB Output: 5V 1A
Charger Output: 5V 700mA x 2
Capacity: 4400mAh
 
Compatibility: 

GoPro HERO4
Apple iPhone 6, 6 plus, 5, 5S, 5C, 4S, 4
Apple iPads
Samsung Galaxy S4, S3

and more models.