amanico
[JLC Moderator]
402205
Good question. I have no idea. We all know that Rolex used it for the Daytona till 2000 and that it was modified ( 28, 800 vph ). But for the other brands, I don't know.
El Primero in other brands?
If/when did Zenith stop allowing the El Primero to be used in other brands?