The initial Royal Oak styles have been fitted with the calibre 2121 motion, which was according to the calibre 2120 made by Audemars Piguet in 1967, the whole world’s thinnest self-winding movement of the period with day indication, and an overall height of three.05mm. The calibre 2121 was also equipped https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/