The SoundTraveller features an on/off switch and an adjustable volume control, so you can have your music as loud or as quiet as you want, whilst the 5 volt mains-in socket allows you to power the unit from the mains or from your computer via USB.
The SoundTraveller will work with any iPods with a dock connector but also has the added benefit of having an audio-in socket, so you can use it with other MP3 players, PDAs, your Sony PSP, your Nintendo DS, CD & DVD players and more!