Great little unit with good sound for the size. I didn't require a USB rechargable speaker as I won't use it that often, so this fits the bill. Speaking of the bill - excellent value and very well made.Like any small device you won't really get much base but sound is loud enough and very clear.
Your MP3 device is acually held in position by the fixed jack plug shown in the picture, which swivels out to switch it on.So depending on where the socket is on your device, it could end up being supported upside side down (like my Sasa Clip),but this really dosn't matter to me.
Takes 3 "AAA" batteries and works well on rechargables.