?AT&T Branded compact, portable, three port, universal compatibility 10,400 mAh premium grade lithium-ion battery, the TenFour external battery pack. This power bank makes for a great emergency backup device any time you can't get to a wall outlet, great for travel or long days on the go! The TenFour keeps you mobile and connected wherever life takes you. Dimensions: 4.7" x 2.8" x 0.9"; Weight: 0.52 lbs. Its has a 10,400 mAh cell A-Grade lithium ion battery, equivalent to approximately 5 phone charges. Rapid charging capability: charges devices twice as fast as standard chargers. Built-in indicator lights show remaining battery. USB charging cable included. Works with any mobile device that has a built-in rechargeable battery, including all iPhone models, iPad, Samsung, Blackberry, Android, HTC, tablet, and other cell and mobile devices.