Rechargeable USB Portable Backup Battery Pack A portable power Boost wherever you go Get a power boost! Boost8400 from Etón is a powerful backup battery pack with an 8400mAh lithium ion battery that provides long-lasting reliable power whenever and wherever you need it. Fast and efficient, when fully charged Boost8400 fully charges most smartphones four times -- and it also charges tablets -- so you"re never caught powerless. Sleek and lightweight With its sleek and elegant design, Boost8400 fits in the palm of your hand. Boost8400 features a Micro-USB DC input to use with most smartphone chargers or computers. It packs enough power to charge tablets and smartphones. With two standard USB ports, Boost8400 can charge two devices simultaneously. An LED charge indicator enables you to monitor the battery charge level when you give it a quick shake. Whether you"re traveling for work, for pleasure, or just around town, let Boost8400 provide the power you need to stay fully charged wherever you are. Features Backup Battery pack with rechargeable 8400mAh lithium ion battery Fully charges most smartphones two times when fully charged Dual USB output to simultaneously charge two devices with a combined output current of 5V=2.1A LED battery charge indicator Shake unit to check battery level Micro-USB DC input for use with smart phone chargers (iPhone block, etc.) Features Boost Turbine 2000 Boost Turbine 4000 Boost Turbine 4200 Boost Turbine 8400 Battery Capacity 2000 mAh 4000 mAh 4200 mAh Lithium Battery Type Lithium Lithium Lithium Lithium Charges Tablets No Yes Yes Yes Emergency Crank Power Yes Yes No No Dual USB Output No No No No Size (in) 5 x 2.2 x 1 5 x 2.2 x 1 5.1 x 2.5 x 1.1 5.1 x 2.7 x 0.6 Weight 7.0 oz 9.0 oz 5.0 oz 7.5 oz