Latexman may be on the right track, it's hard to tell from the VNE web site if this is the fitting.
MikeHalloran, you are right, it appears some people may be commenting on a different fitting. There are a bunch of photos on the FLIKR site, and when I pulled it up, I had to scroll through the previous photos top find what Chemeng421 was talking about, i.e. with the several rings that, as you say, could be likened to cooling fins on an engine cylinder.
Chemeng421: It would have helped if you had only put up the photo(s) to which you were referring, also if you had an idea of the size (looks like it could be quite a large nozzle?) It may well be some kind of manwya fitting for sanitary (food grade) equipment. If there are any dairy workers or dairy farmers in the forum, some of them may recognize it.