They're 1/4" NPT. Here's a view of a valve needle withdrawn.
Talk about 'obscure'. There's a CARP Industries Corp. in Florida that deals in aircraft parts, but they appear to be completely unrelated to this 'CARP' -- they have a different logo altogether. Here's a close-up of the logo on these valves.
I managed to find that 'exact' logo, but with the name 'FUJIKIN' added. FUJIKIN CARP is a Japanese firm that does make stuff like this. They have a brief article on their website about the significance of 'CARP', and what all is symbolized by the rest of the logo. (Be warned -- the corporate bushwah in there is gag-inducing.)
Anyway, I have a couple of exquisite valves here that I'm unlikely to ever have need of, but, you never know. I'll stash them in the box where I keep similar items.
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