Attractive and well-built USB backup battery. With a capacity of 4000 mAh, it will buy some time, but modern smartphones take more than 1000 mAh per charge, so don't expect miracles.
Even my ancient iPod 30GB is willing to charge from it, and that device is finicky with chargers.
Note: This is an external power brick. It connects to any compatible device using a USB cable. There was a prior review talking about cases, volume and shutter buttons, but that was a different product entirely.