Digipower Universal USB Portable Charger 3400mah
Charging your devices using the Digipower battery pack by simply plugging your USB power device in the "OUT" connection. With the built-in rechargable 3400mah lithium-ion battery, this battery pack can extend the battery life for your USB power devices any time you need it.
Additionally, This battery pack can be converted into a battery "Bank" by connecting several of the battery packs in series, Battery pack 1 (Output) to Battery Pack 2 (in) then USB Device Connected to battery pack 2 (Output). With this setup, you can double your hours of charging. This setup is great if you plan to be away from an outlet for an extended amount of time. To recharge battery bank, simply plug into an USB outlet or 12 volt car USB converter.