Rolex GMT Master 16700

First released in 1954, the GMT-Master was a joint effort by the watchmakers at Rolex and pilots at Pan American Airways. This resulted in the ref. 6542, which utilised the base movement and case from the Turn-o-Graph ref. 6202 (which developed into the Submariner) and modified it to include the now-famous 24-hour hand and two-colour bezel. Later models replaced the fragile bakelite bezel with an aluminium one, enlarged the case, and allowed the 12-hour hand to be independently set.