When it was introduced in 2012, the Sky-Dweller was a technological powerhouse, incorporating an annual calendar, and dual time that could be set by the crown and switched between using the rotating bezel. It was previously available only in precious metals. But in 2017, Rolex has released Rolesor (steel and gold) versions, such as the Ref. 326933 pictured here with a steel case and yellow gold bezel, crown and centre bracelet links. Seconds function remains.