The first Royal Oak designs were fitted with the calibre 2121 motion, which was based on the calibre 2120 created by Audemars Piguet in 1967, the whole world’s thinnest self-winding motion on the period with day indication, and an Over-all height of three.05mm. The calibre 2121 was also Geared up https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/