Dear Forumners!
I could not trace two main points of the Sinn 142 production:
1. when was sapphyre glass (inside AR coated) introduced after mineral glass?
2. When was screw-down crown introduced after non-screw-down crown?
I have catalogs only from 1994 and later so I do not know: looking for a brushed/polished 142 St with sapphyre glass and screw-down crown, wanna know which years to look after? (End of brushed/polished case production is known for me, so it is not a question).
Thanks for any kind input, also a copy (scan) of the UM test about the 142 St is welcome! (I think cca. year 1991).
Best regards:
Robertusz
German reply is also welcome!!!