If every world time watch references Patek Philippe's efforts, then every GMT watch can be said to reference the Rolex GMT-Master. Introduced in 1954, Rolex has been tweaking this piece for more than 50 years, underscoring its position as the unassailable tool of choice for the professional jet-setter. In fact, this year marks a rare instance of distinctive change in the GMT-Master.

Nevertheless, all the trademark characteristics of the GMT watch are reflected here. The GMT hand is the one with the distinctive triangular tip (luminous in this version) and it points to the markers on the bezel. The current watch sports a ceramic bezel that does away with the model's trademark blue and red markings. Marked on a 24-hour scale, the bezel can be rotated to fit any position you desire.

Like Patek Philippe's Ref. 5131, setting the time here is the model of simplicity. A single crown controls all operations, including the date. The setting of the hour hand and the hand with the luminous tip is entirely separate. This means that each can be set independently yet with the same crown.