Rolex GMT-MasterFasten your seatbelts for the story of the inimitable Rolex GMT-Master! As civil aviation took off after World War II, airlines began to fly over longer distances. As a result, pilots required accurate watches that could display multiple time zones simultaneously. In the early 1950s, Pan American Airways (Pan-Am) requested Rolex to develop a watch for this very purpose. The GMT-Master (‘GMT’ standing for ‘Greenwich Mean Time’) was introduced in 1954. It featured a 24-hour hand alongside the regular 12-hour hand. In combination with a bidirectional 24-hour bezel, this GMT hand could be used to read the home time zone while the 12-hour hand displayed the ‘local’ time.Despite its close links to aviation and its professional purpose, the Rolex GMT enjoys a fanbase far beyond the pilots it was originally intended for. Over the years Rolex has introduced many wonderful variations of the GMT: take your pick!Ref. 1675The ref. 1675 GMT-Master replaced the legendary ref. 6542 in 1959 and enjoyed an unusually long production run: over 20 years! The first 1675s received the well-known ‘pointed crown guards,’ which were replaced by regular rounded crown guards in 1964/1965. The dial of the 1675 also changed over time, starting with a glossy gilt chapter ring dial and ending with a matte radial dial (with significant variation in between, like the rare ‘exclamation mark,’ ‘underline’ and ‘Double-swiss’ dials).The 1675 was produced mostly in steel but was also available in 18k yellow gold or bicolor (steel and gold). The 1675 was the first Rolex ‘tool watch’ for which a factory-fitted jubilee bracelet was an option, starting in the early 1970s.‘Pepsi’ bezelThe red/ blue bezel inserts on steel GMTs are often referred to as ‘Pepsi bezels’ because people associate the color scheme with the famous soda company. However, the colors red and blue were actually taken from the Pan-Am logo and meant to indicate day (red) and night (blue).The Pepsi bezel was available for nearly sixty years until it was discontinued in 2007. In 2014, Rolex relaunched the beloved Pepsi bezel with the new Cerachrom insert, which was only available on the white-gold model. At Baselworld 2018, the Pepsi was reintroduced on a stainless steel model.