The Rolex Oyster Perpetual Sky-Dweller was introduced in 2012 and is one of Rolex' most complicated watches to date. It features an annual calendar and a second time zone function. The former has a regular date display, while the month is displayed through apertures by the hour markers. The latter is indicated through an off-centre 24h disc at 6 o'clock. The well-known fluted bezel functions as sort of a gear box with three positions, enabling the user to set the date, local time and second time zone through one single position on the crown.
Calibre 9001 is a self-winding mechanical movement entirely developed and manufactured by Rolex. Introduced in 2012, it is one of the most complex calibres ever created by Rolex watchmakers. Nonetheless, it is engineered to ensure simplicity of use: a selector wheel on the outside edge of the 9001 ensures the interaction of the movement and the bezel of the watch to set the Sky-Dweller’s functions. Like all Rolex Perpetual movements, the 9001 is a certified Swiss Chronometer, a designation reserved for high-precision watches that have successfully passed the Swiss Official Chronometer Testing Institute (COSC) tests. Its architecture, in common with all Oyster watch movements, makes it singularly reliable.