I gained this external battery set because of my MP3 player's battery failed and it would have been too cumbersome, this return them, and since my warranty had expired. I have to say I am thrilled with this unit. Just hang on to an MP3 player via cable, and you can run it far longer than the original battery. In addition, the device is so small that it easily along with the MP3 player fits in the pocket or jacket pocket. The battery lasted with my players have always been about a week before I had to recharge it. Another advantage is the cable set, with which it is possible to charge and all popular mobile phone models. The only defect that has occurred in several months use, unfortunately, a bad contact at the connection cable between Varta V-Man and MP3 player was (by storing the equipment in my backpack, I suspect). But I was when I sent an email to Varta, within about 2 days a new cable sent free by DHL. I can only recommend, if you fail a rechargeable, built-in battery in an MP3 player or you need a mobile charger on the go for other devices, set to this!
