…. The IWC "Bund" are fairly rare versions of the IWC Ocean 2000 "Porsche Design", custom made for the German combat divers. There are several "Bund" versions but they all have one thing in common: the case-back has engraved on the inside among others: the individual watch number and the reference number (in this case: 3509). On the outside of the case-back it reads: "Bund" followed by the NATO number (6645-12-xxx-yyyy) and again the individual watch number.
There have however been very few IWC "Bund" spotted that have the correct "Bund" markings on the inside of the case-back including the Bund related reference number (in this case 3509) but where the outside of that same case-back is missing the Bund related markings. This watch below is one of those.
The unconfirmed story behind: IWC was back in time owned by a company called VDO. And the watch was a design collaboration with Porsche Design. And the story goes that a handful of IWC Bund watches were delivered to either VDO executives and/or executives at Porsche Design in Salzburg. And given they were earmarked for delivery to the executives and hence not for military use they did not engrave the "Bund" markings on the outside of the case back. But they correctly have all the other specific "Bund" attributes including the Bund reference number.
Vintage watch collecting is full of mysteries!
Cheers, HSTE