I have a similar tool but made by Hazet, of the vintage beetle spare tire tool kit fame.  It is different in that the end of the tool which holds the Allen is bent and the Allen slides in and out of the end giving you some additional flexibility to reach hard to access drain and fill plugs.  I use it on my Vanagon, my Rabbit pickup, and my old bugs and buses.  It gives me extra comfort knowing that the tool if from the Fatherland.  

Tom

Daryl Christensen <daryl@AATRANSAXLE.COM said:

As far as I know..(and I have looked many times for another use, it being a21 mm...It's for the very early split case tranny drain and fill plugs..Go figure they would still put an antique tool on one end of a perfectlygood 17mm toolDaryl of AA Transaxle425-788-4070"On the cutting edge of Old technology"