“Every single manufacturer attempted to have logic within their numbering system but unsuccessful miserably,” Mandelbaum continued. “It just represents the entire absurdity with the Swiss seeking to think of a numbering method. Although the crystals over the 160xx generation of Datejust watches remain comprised of acrylic, the sloped "pie pan" https://www.watchesworld.com/a-history-of-watch-reference-numbers/