After World War II, Rolex began developing tool watches for various professions. In 1954, the company released the Submariner and GMT-Master, both of which featured rotating bezels. The GMT-Master was the result of a joint venture between with Pan American World Airways, which had requested a watch to help pilots keep track of both local and GMT time. They supposed that a pilot could sleep on their regular schedule and avoid jet lag regardless of where they were.
The GMT-Master is based on the Rolex Datejust Turn-O-Graph, launched a year earlier, which had a rotating bezel for timing. The bezel on the Turn-O-Graph, marked in 60 increments with numerals every 10 marks, was designed to be lined up with the minutes hand. In this way, one could count elapsed minutes.
The 1955 GMT-Master Ref. 6542 was quite different. Rolex added an additional central hour hand to the movement, geared 1/2 the normal one, so it rotated once every 24 hours. The Plexiglas bezel was marked with 12 increments, alternating dots and numerals. It could then be rotated forward or back and read with the 24 hour hand to show GMT time on the bezel, while the smaller 12-hour hand would show local time using the dial. This system was quite easy to read, though not quite as user-friendly as modern GMT watches with an independent hour hand. The Ref. 6542 strongly resembled the contemporary Submariner Ref. 6200, with no numerals on the dial. This first GMT-Master used Cal. 1036, Cal. 1065, or Cal. 1066.
Rolex updated the GMT-Master and Submariner in 1959 with crown guards and an aluminum anodized bezel. The GMT-Master Ref. 1675 is regarded today as the quintessential example of the model, though it also did not have a true independent hour hand. This updated GMT-Master used the 18,000 A/h Cal. 1565 until 1965 when it was updated with the 19,600 A/h Cal. 1575. This lasted in production until 1980, when it was updated to become the Ref. 16750. Cal. 3075 in the GMT-Master Ref. 16750 was the first GMT-Master to offer a quickset date function, and it also operated at 28,800 A/h. It is considered a transitional model today, being only produced until 1988.
In 1983, Rolex introduced the GMT-Master II, Ref. 16760, which was the first to offer an hour hand that could be set independently. The case is extra-thick to accommodate this larger Cal. 3085 movement, giving rise to the nickname “Fat Lady” today. Like the contemporary Ref. 16750, this model was only produced until 1988.
Rolex updated both the GMT-Master and GMT-Master II in 1988 with a sapphire crystal and new case. The lower-end model, Ref. 16700 with Cal. 3175, still lacked an independently-adjustable hour hand and was labeled “GMT-Master”. The Ref. 16710 GMT-Master II had the independently-adjustable hour hand, thanks to Cal. 3185. The simple GMT-Master Ref. 16700 was phased out in 1999. while the GMT-Master II continued through 2007.
Rolex introduced an updated GMT-Master II in 2005, now with larger lugs and crown guards (giving the impression of a larger case overall), Triplock crown, a green 24 hour hand, Cerachrom ceramic bezel, new movement, and Cal. 3186. The first to be released was the yellow gold 116718LN and an anniversary model with a green bezel. The two-tone (steel and yellow gold) Ref. 116713LN was introduced at Basel Fair 2006, followed a year later by the all-steel Ref. 116710LN. The “Batman” Ref. 1116710BLNR was introduced at Baselworld in 2013, the first Rolex to feature a bi-color ceramic bezel. The famous “Pepsi” bezel was retired in 2007 because Rolex could not produce a ceramic bezel insert in the correct shade of red. This was rectified in 2014 with the introduction of a white gold Pepsi model.
In 2018, Rolex introduced an updated GMT-Master II, Ref. 126710, with Cal. 3285, and retired the previous references. This new movement boasts 70 hours power reserve, while the look of the watch is updated with a Cerachrom bezel. A “Pepsi” model is once again available in steel, but the former models remained in production as well. In 2019, Rolex introduced an updated “Batman” model with the new Cal. 3285 movement and Jubilee bracelet.
Rolex GMT-Master II Ref. 16710A “Coke” bezel
One aspect of the GMT-Master and GMT-Master II is the use of two-tone bezels. This was part of the original spec for the model, and the longevity of certain color combinations has added to the affection of Rolex collectors. In all cases, the color changes at 6 00 and 18 00 on the bezel, indicating day and night.
The classic GMT-Master color combination is “Pepsi”, so-called for the red and blue bezel. This iconic Rolex timepiece has been in the lineup since the very beginning, debuting in 1955 as the original GMT-Master, Ref. 6542. This first model featured a luminous bakelite bezel which was prone to cracking, so Rolex replaced it with a metal insert in 1956. The Ref. 1675 followed in 1959 and was produced until 1980. The next model switched to a new movement and Jubilee bracelet Ref. 16750 was produced from 1981 through 1988.
When Rolex switched to Cerachrom ceramic bezels in 2007, they were unable to produce an acceptable two-tone combination. Therefore, the Pepsi went on hiatus for almost a decade. When the Ref. 116719BLRO "Pepsi" was finally unveiled in 2014 it featured a white gold case and appropriately high price tag. The “Batman”, introduced a year earlier, was the only steel two-tone offering.
An Oystersteel model was reintroduced in 2018 with a Jubilee bracelet, anchoring the new-generation Ref. 126710BLRO GMT-Master II line. This was joined by another white gold model, with blue or meteorite dial, in 2019.
The original “Root Beer” GMT-Master featured a two-tone brown and cream bezel. This Ref. 16753 also featured a brown dial and two-tone steel and yellow gold case. It is also sometimes called the “Nipple Dial” due to the use of gold pips as markers. These pips resemble a precious stone, giving the watch another name “Tiger Eye” or “Tiger Augen”. Yet another name for this reference is “Clint Eastwood”, after the American actor of the same name who favored it. These were produced through the 1980s.
Rolex brought the “Root Beer” look to the GMT-Master II in 2018 with the introduction of the new Ref. 126711CHNR and 126715CHNR in Rolesor and Everose, respectively. These feature a brown and black bezel rather than brown and cream, and the dial is black rather than brown.
The black and red bezel of 1983's GMT-Master II Ref. 16760 earned the nickname “Coke”, likely in response to the existing “Pepsi” name. This model anchored the GMT-Master II line until the Pepsi joined it in 1989 with the new Ref. 16710. These were produced through 2007, and the Coke model has not been seen since.
The newest named color combination was introduced in 2013. “Batman” has a blue and black bezel and black dial, technically “Lunette Noir” or Ref. 116710BLNR. Rolex was unable to produce a blue and red bezel yet, so “Batman” was the only two-tone Cerachrom model for a year. This model was updated with a new movement and Jubilee bracelet in 2019 as Ref. 126710BLNR. This time, Batman followed Pepsi by a year.
Rolex officially calls these models the “Rolex Oyster Perpetual Date GMT-Master” and “Rolex Oyster Perpetual Date GMT-Master II” to reflect the “Oyster” waterproof case, “Perpetual” automatic movement, and Date complication. These additional terms are commonly omitted in modern times, even by Rolex.
The GMT-Master lacks an independently-adjustable 24-hour hand and uses the rotating bezel to “set” the remote time. The GMT-Master II has both an independently-adjustable 24-hour hand and rotating bezel and can thus be used to read three time zones at once.