The primary Royal Oak models were being equipped with the calibre 2121 motion, which was dependant on the calibre 2120 developed by Audemars Piguet in 1967, the world’s thinnest self-winding movement of your period with day indication, and an Over-all height of 3.05mm. The calibre 2121 was also Outfitted using https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/