Continuing to celebrate 50th birthday of El Primero here on WatchProSite
By: Ares501 - Mr Green : January 14th, 2019-11:57
I have a feeling this will be whole year series of posts Between 1966 and 1967 Zenith’s management decided to create the first ultra-thin, high-frequency integrated automatic chronograph calibre, beating at 36,000 vibrations per hour and thus able to meas...