Female Self Sealing Coupling - 1/4" tube with 3/8 Body, Female Half
This is the coupling used in all CU-100 Cold Machine and CU-200 Super Cold Machine. The Female half has internal threads on the coupling.
There were a few years where two different coupling types were used. During those years the standard was the one-time use piercing coupling that once screwed together would pierce the thin metal cover one the mating end of the coupling. This self sealing coupling was an upgrade at that time. As far as we know, this self sealing coupling is now the standard (only choice) for the CU-100 Cold Machine and CU-200 Super Cold Machine.