Well, John, your first reply sounds good and that´s just how I think that things were going

On your new theory, though... well, I´m just not sure. Field testing and Rolex? Why do they always need years and years of developement before they come up with something new? I guess they *do* test but that´s rather the employees who wear around a watch for some time before it hits the stores.

I would rather think that the old 4130 hairspring was not as antimagnetic as the new PB hairspring but they keep on telling people that the 4130 always had the PB so that people wouldn´t complain.

But as you said: What do *we* know, and how can we tell without an analysis?

Best-
Nico