I ahbe me this device for a flight to America bought because the battery from the iPod does not last particularly long, the device works properly, but is much larger than I thought. The price is good compared to other external batteries, the processing is not perfect production costs probably not even be 1, but that's as long as it funktioniet matter. Filled with batteries, the device is slightly heavier than the iPod. Well, that you can fill batteries to repeatedly. How long the battery lasts, I could not test. All in all, a good device with little weaknesses.