TomKxx
234
GS started making 9S movement since 1998. 1st was 9S55, later 9S55A to 9S65
9S55 to 9S65, GS used MEMS to make lighter enscapement.
That’s all I know, I’m not sure what was done from 9S65 to 9S64 & 9S63.
MEMS : microelectromechanical system (by Epson)
