“Each model attempted to have logic in their numbering process but unsuccessful miserably,” Mandelbaum continued. “It just signifies the total absurdity in the Swiss trying to think of a numbering system. Even though the crystals on the 160xx era of Datejust watches remain created from acrylic, the sloped "pie pan" https://www.watchesworld.com/a-history-of-watch-reference-numbers/