No batteries are needed as the speaker is passively powered as soon as you connect an MP3 player or whichever source you want using the easily-storable 3.5mm cable plug.
Adapting a powerful nedymium magnet that's also magnetically sheilded, you get a suprsingly powerful sound from such a small system.
Lastly, with a foldable mechanism, your speakers are protected at the same time as taking up very little space in your bag when not in use.
Keep it simple. Keep it stylish. Keep it Sony and dont leave home without it!
Key features:
Single box stereo speaker design
Magnetically sheilded
Plug-in power
Storable cord
Built-in speaker stand
Lightweight, thin chassis
$7.95 Shipping is quite steep for such a small item.