Thojil wrote on Mon, 01 July 2013 06:47

Interesting info Paul. 1902 is the earliest ad I have seen so far of their Swiss Extra Precision movements that Gruen started to market. The assumption is they started as early as 1900 with these movements, based on an article published in "The Jewelers' Circular - Weekly and Horological Review, February 28, 1900, pp. 33-4". Still don't know who actually produced these movements? Some assumed it was Aeby&Landry, but I researched that this can't have been the case.

By the way, I see they were also available in 00 size. I know 0 size is 13''' and 1 size is 13 1/2''', so is 00 size 13 1/4'''?

MY BOOK HAS 2/0 {00): 12 3/4''' art b.


EXTRA PRECISION I ASSUME YOU MEAN TO BE THE FIRST MADRETSCH MARKED BEST 21j Verithins also usually marked EXTRA as well as PRECISION. The 131K without EXTRA MARK is 1905-8? 144K marked EXTRA is after 1910? art b.