Always distrusted the Jvalve rods. Seems like they always liked to catch on things. Did like the J lever (on valve) when it was in operating position with lever up and aimed at the back. Or also the lever aimed at the back and pointed down. To activate you needed to move the lever up. I believe the lever down and aimed at the back was originally thought up by cave divers to prevent accidental activation of the reserve function.
The advent of the SPG and later computers made the reserve valve a thing of us vintage guys. Course likely (me especially) never paid any attention to the crazy things. Ya'll remember the famous "knocker" valve that USD marketed. Another gimmick (by my standards).
Anyway, the rods make great lobster ticklers.....