This power bank from the house of Promate is a perfect choice for all those who travel frequently. The Promate Armor 9000mAh Tough Rugged Dual Ports Power Bank Made of Military standard Aluminum for All Smartphones and Tablets is compatible with all Android Smartphones and tablets. It ensures fast charge on the go with the aid of USB port that is compatible with all the devices that charge through similar ports. The lithium ion battery when fully charged holds power to charge any modern smartphone up to two or three times. It features auto power function i.e. it automatically turns of when not in use. This power bank has a capacity of 9000mAh.