After constantly charging and re-charging the iPod, the battery eventually loses its ability to hold a charge and needs to be replaced. This is a user-replaceable internal battery for the Apple iPod 3rd generation and is intended for out-of-warranty iPods only. The 3rd generation iPod has a click-wheel and 4 control buttons just above the click wheel. Video installation instructions available online at www.ereplacements.com. Fits with compatible part numbers: 616-0159, E225846.