The 1st Royal Oak versions ended up equipped with the calibre 2121 movement, which was determined by the calibre 2120 made by Audemars Piguet in 1967, the world’s thinnest self-winding motion with the era with date indication, and an overall height of 3.05mm. The calibre 2121 was also equipped using https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/