Well, the Efika power connector is a standard ATX one so you can plug in any standard PC PSU that you like. Of course it will be an overkill (both size and current wise), so most Efika owners used a PicoPSU instead. PicoPSU requires an external brick adapter that can supply it with 12V (I vaguely remember that I had a 90W version of PicoPSU with 12V 5A external brick).

If you need to refresh your memory about Efika - there's the Efika Book available on morphos-storage.