It works via 240v or AA batteries. Works fine but the volume output when on AA's is not that good. Recently tried a 12v multi plug type thing from Maplins to power from lighter socket, worked a treat - i - Station plays like it's plugged in at 240 socket, load enough not to **** others off.
I bought this from Maplins a few weeks ago. It is to power my laptop & works from the 12v ciggy lighter. As you can see from the write up, it has a variable voltage (which I tested & found that it was outputting below the stated voltage, but it still managed to charge my lappy) & also has a USB powered output. All for 15 quid!! result!