Hello gkmaia ! 🙂 Was looking around for you, but was also
having a tough time tracking these down. Seems like different
shops have everything but that stem, or Tag Heuer stems in
general. Was thinking maybe see if tag Heuer themselves
has them. They just might have them.
I originally was thinking you could simply get a regular stem from a bass ETA / Ronda movement, but upon researching the movement, it looks to be proprietary to Tag Heuer. You may have to get the stem through an AD, if they will sell it to you, or try to find a parts watch...