Correct me if I'm wrong, but doesn't the Cubid case already have a DC-DC converter? So this plug is really just an extension cord, right? It basically won't work for anyone unless they have a Cubid case [http://www.koolnquiet.co.uk/index.ph...=104&cat_id=32].
However, considering that the cases come with stuff... are they usable as a carputer? The AC-DC conversion (AFAIK) is done outside the case using the included PSU.
Which of course has been discussed before (but not limited to):
A 12v dc-dc 12v power supply