The “Datejust” identify had turn into a permanent fixture on its dial, and other attributes such as the arms, bezel, hour markers, and crystal (with cyclops magnification lens) took types that are still a great deal current on the modern Datejust watches that Rolex manufactures these days. 100M Waterproof: Using https://www.watchesworld.com/a-history-of-watch-reference-numbers/