The Logitech mm50 Portable Speakers for iPod uses 3" pressure drivers to maximize bass and minimize distortion. The rechargeable Li-ion batteries last up to 10 hours, and you can charge both the speaker system and iPod battery simultaneously. Using 3-D sound processing that "widens" the stereo effect, this system's sound seems to come from an area about two feet wider than the speaker itself. And with a custom travel case, you can take the big sound from this small package anywhere.