It appears to be an old but standard quarter-inch ID fitting. Could have come from just about anywhere ... except a U boat with metric fittings. Sorry, but it seems pretty unlikely.
EDIT: And Lunkenheimer is based in Cincinnati, OH. Admittedly, that town's chock full of Germans ... who've all been Americans for 250 years like my family.
Weasel Wrote:It probably did come from a US warship though from WW2, or at least a parts bin!!
Having crawled around the USS Texas and USS Lexington with my boys four times in the last three years, I can verify that there's about a zillion places onboard that valve may have been in use ...
I wouldn't put it back in use, however. WWII-era fittings leaked.