Found this this morning at my local,friendly flea market. Talked to the Mercedes parts people to understand more about the wrench's provenance. Turns out it was used on 190 220, and 280 SL cars (Those sexy two-seaters). It was also used on the unsexy190 4-door sedan. The 17 mm socket will work on today's Mercedes. Dowidat made this, and this fact is stamped on the back
I hurried home with this prize, cleaned it up, so I can put it on eBay tonight!