i just got some couplers today. from what you're showing there, it would be hard to tell. it might be for a sankey, but of the 3 i got, they're all very similar but one doesnt work because of the shaft length. i would suggest taking it apart (pretty simple) and posting some more pics. I just disassembled all of mine to thoroughly clean so could take a look, maybe even take measurements of the ones i have for you to compare to.