(Approximately) when did the swan's neck regulator first appear?

I'm referring to those used on V&C models, of course.

Thanks in advance.

Regards,

Tony C.

if you are talking about wrist watches it seems that the first use of
11/30/2007 - 09:43

the swan neck fine adjustment was with cal 453 in the early 40s. However, in the 30s and 20s VC's movements did not systematicaly have reference numbers and it could be possible that the swan neck fine regulation was used here and there.