Logitech S315i and S125i is a new rechargeable speakers with iPod dock which will allow you to have a full day music tuning for a single charge. This is wonderful for outdoor usage where no power source available for recharging. However, there is no detail mentioned about how many hours it should operate on single charge.
The Rechargeable Speakers also has a dock that you can use it for recharging your iPod or iPhone (the S315i model) and the S125i is the Boombox type or easy-to-transport speaker with docking station, but without iPod recharging functionality. Both speakers can connect to any music players using the provided 3.5mm auxiliary input and they will be able to support all iPod/iPhone generation via Apple’s Universal dock connector.