Power your Contax Real Time Winder externally with this power pack. Toss in the AA battery insert from your Real Time Winder and hook your camera up with the included power cord. Why would you do this? Well, if it’s cold out, you can stash this holder in a pocket and prolong your battery life. It’s quicker to swap batter inserts, too (inserts are not included). In good condition, with some splitting in the finish of the external vinyl case.