Jerry, That looks exactly like one I'm holding in my hand. It actually has a WIDE (2-3mm) single groove - from all the distortions from the reflected chrome in that groove it just looks like a couple thin rings (like you'd see on TA cups). My identical fixed cup definitely be a righty-tighty,... so yer lookin' at a French thread.
Enjoy!
Bob Hanson, New Mexico (Nous parlons Français ici) USA
Jerry Moos wrote:
"Sutherland's says 1 ring is French, two rings English. But what constitutes a "ring"? The cup shown has one separate raised section, separated from the rest of the cup by two recessed circles inscribed in the surface of the cup. Is the raised section one "ring", or is each recessed circle a "ring", meaning this would be two "rings"?"