Rolex Sky-Dweller black dial with bi metal oyster bracelet. What establishes the Sky Dweller as the most complicated rolex movement is it dual time-zone function.
Sitting below 12 o'clock on the dial of the Sky-Dweller is a small red arrow. This arrow points towards an off-centred rotating disc on which sits a 24-hour scale. This arrow and ring indicate your reference time, which could be for example your home time.