While the Rolex Submariner often steals the spotlight as the brand's most iconic watch, the GMT-Master series is equally renowned and arguably the quintessential traveler's watch. Born in collaboration with Pan Am Airlines in 1955, the GMT-Master was designed for pilots navigating multiple time zones, a fitting companion for the growing age of commercial aviation. Over time, it evolved alongside the Explorer II, another GMT-equipped model, but the GMT-Master stood out with its rotating bezel and later, an independently adjustable local hour hand, which was introduced in the GMT-Master II.  The Rolex GMT-Master (Pre-GMT-Master II) The original GMT-Master (ref. 6542) made its debut in 1955, tailored to the needs of long-haul pilots, especially those flying international routes. Its introduction coincided with the rapid expansion of global air travel. The watch featured a 38mm Oyster case with a distinctive bidirectional rotating bezel made of Bakelite, a plastic material used in the first models, which gave the watch its "Pepsi" bezel - half red, half blue. The red indicated daytime hours, while blue represented night. This bezel design became an iconic feature of the replica Rolex GMT-Master series. The GMT-Master quickly gained popularity with US Air Force pilots and astronauts. Notably, it was worn by NASA's Jack Swigert during the Apollo 13 mission, and Stuart A. Roosa wore a GMT-Master on Apollo 14. These watches became emblematic of the era, associated with both aviation and space exploration.  GMT-Master Ref. 6542 (1955-1959) The 6542 featured radium-based luminous markers, which posed safety risks and led to a class-action lawsuit in 1961. As a result, many of the Bakelite bezels were replaced with anodized aluminum inserts. Despite the issues with its early materials, the 6542's aesthetic and functionality cemented its legacy. This reference also introduced the use of chronometer-rated movements, with the calibre 1065 powering both the steel and gold models. Notable variations included gold models with brown bezels and an alpha hand set, which distinguished them from the steel versions. GMT-Master Ref. 1675 (1959-1980) The 1675 is the longest-running reference in the GMT-Master lineup, produced for over two decades. It saw significant updates, including a shift to an anodized aluminum bezel, a 40mm case size, and the introduction of crown guards. The dial evolved from glossy gilt to matte black, with the tritium-based "T<25" marking appearing by the mid-1960s. By 1963, the "exclamation point" marker was added to some models, indicating the use of less radioactive tritium. In 1964, this was formally noted on dials with the "T" designation. The 1675 continued to develop with refined movements, like the calibre 1565, which incorporated microstella regulation for greater precision. Throughout its production, the 1675 was available in various configurations, including gold and two-tone versions, with some models gaining fame in the 1960s through advertisements featuring Concorde pilots. GMT-Master Ref. 16750 (1980-1988) The 16750 introduced practical improvements like a quick-set date function and a more robust 100m water resistance. Aesthetic changes included a transition to glossy lacquer dials with white gold indices. While the reference maintained the matte dials of its predecessor for a time, some later models were prone to cracking, earning the nickname "spider dials." The 16750 also marked the last days of the traditional GMT-Master, paving the way for the more advanced GMT-Master II. GMT-Master Ref. 16700 (1988-1999) Produced alongside the GMT-Master II, the 16700 continued the legacy with minimal changes. Its calibre 3175 movement offered enhanced precision, though the GMT-Master remained limited in its ability to track multiple time zones compared to the GMT-Master II. By the end of its production, tritium had been replaced by Super-LumiNova, reflecting Rolex's continued efforts to modernize its iconic series.  The GMT-Master II Era GMT-Master II Ref. 16760 (1982-1988) The GMT-Master II, launched in 1982, represented a major leap forward with the introduction of the calibre 3085, which allowed the local hour hand to be set independently from the 24-hour hand. This innovation enabled users to track a third time zone, setting the GMT-Master II apart from its predecessor. The reference 16760, known as the "Fat Lady," featured a thicker case to accommodate the new movement. It also introduced the Coke bezel - red and black, signifying day and night. GMT-Master II Ref. 16710 (1989-2007) The 16710 offered a more refined version of the Rolex GMT-Master II, with a slimmer case and a new calibre 3185 movement. It remained in production for nearly two decades and was available with Pepsi, Coke, and all-black bezels. Notably, the late models introduced the calibre 3186 with the innovative Parachrom hairspring, enhancing shock and temperature resistance. This reference also saw the introduction of the iconic "stick dial" error variant, a rare collector's item today. GMT-Master II Ref. 116710LN (2007-2019) The 116710LN brought a significant update with the introduction of the Cerachrom ceramic bezel. This development made the bezel more durable and resistant to fading, a notable improvement over previous aluminum versions. The model also included the calibre 3186 movement and a new "green hand" aesthetic for the 24-hour hand, creating a striking visual identity. The 116710LN was followed by the introduction of more bezel variants, including the Batman model (ref. 116710BLNR), which featured a dual-colored bezel - a first for Rolex. GMT-Master II Ref. 126710BLNR "Batman" (2013-2019) The "Batman" bezel, combining blue and black ceramic, was a game-changer. This reference, powered by the calibre 3285, was the first GMT-Master II to feature a ceramic bezel in this unique two-tone design. The 24-hour hand was also updated to match the blue bezel, adding to the model's visual appeal. The 126710BLNR became a sensation among collectors, thanks to its modern design and innovative bezel. GMT-Master II Ref. 126710BLRO "Pepsi" (2018-Present) The return of the "Pepsi" bezel in 2018 was a momentous occasion for Rolex fans. This time, the ceramic bezel was perfected, with the steel version of the replica watch now available to the public. Powered by the new calibre 3285, this reference introduced several technological improvements, including a longer power reserve and the use of the Chronergy escapement for greater accuracy and efficiency. GMT-Master II Ref. 126720VTNR "Sprite" (2022-Present) The 126720VTNR model was a bold departure, featuring a two-tone green and black bezel and, for the first time, a crown positioned at 9 o'clock, making it a left-handed edition. This design choice generated mixed reactions but further solidified the GMT-Master II as a series that constantly pushes the boundaries of innovation. GMT-Master II Ref. 126710GRNR "Bruce Wayne" (2024-Present) The 126710GRNR, with its bi-color grey and black bezel, is the latest addition to the GMT-Master II lineup. Known as the "Bruce Wayne" for its subtle, sleek appearance, this reference continues Rolex's tradition of blending classic designs with modern technology, offering a refined take on the iconic traveler's watch. [video width="720" height="1280" mp4="http://www.functionalobjects.com/wp-content/uploads/2025/01/20250124watch.mp4"][/video] A Collector's Dream The GMT-Master and GMT-Master II series remain highly sought after by collectors. Early models, such as the 6542 with original Bakelite bezels, and the 1675 and 16750 with rare dial variations, command significant premiums. Collectors are particularly fond of the vintage "Pink Panther" and "Concorde" variants, as well as the gold models. Modern GMT-Master II models, especially those with unique features like the Batman and Pepsi bezels, have also garnered immense popularity. However, due to their limited availability, acquiring these models can be a challenge. As time progresses, vintage models continue to appreciate in value, making them a worthy investment for collectors looking to own a piece of Rolex history.