In the meantime, there’s some evidence that Intercontinental distributors hated the inconsistent and sometimes illogical numbering methods of their Swiss overlords. While the crystals over the 160xx technology of Datejust watches are still made out of acrylic, the sloped "pie pan" type dial from the preceding technology is gone, and https://www.watchesworld.com/a-history-of-watch-reference-numbers/