$18.95 on Amazon and rated 4 stars:
*Unparalleled large capacity 5000mAh provides 3 extra charge for iPhones and 2 extra charges for Samsung Galaxy Notes. It extends 30 hours of talk time or 40 hours of video play back time for iPhone 4/4S, iPhone 5 or most other mobile devices.
*Compact, portable and stylish design. Convenient to carry in pocket or purse and is perfect for on-the-go reliability. Built-in bright flash light helps light up your way home during the dark late night.
*Designed with over-charge and short-circuit technologies the Enerpak Tube is a safe and reliable source or re-chargeable power. Using 1A output charging current, which is powerful enough to charge most Mobile phones and Tablets.
*The Enerpak Tube is compatible with all USB chargers & cables come with your Cell phone or tablets, so there is no AC adapter or Apple Cable included.