Yes, it requires a 9 volt d.c. supply. These units are available at most electronics shops, for about £10-£15. They have standard concentric plugs to fit the Looper. The Looper does not come supplied with one. Guitarist magazine published a review of the Ditto Looper last year (I forget which month), which can be found online.
The unit is too small to take a battery... There is no power supply provided so you have to get your own..£12 at Maplin...Don't bother with the one that's advertised for it as it's way more expensive than that...as long as you get one that is correctly rated you'll be fine. Other than that the little unit is excellent!
This unit is tiny - you'll note the input/output jacks are not parallel as otherwise the jacks would meet! There is no room for a battery, so you'll need a 9v power supply. Great, simple to use pedal though!