When moving from a three-hand watch to a model with additional functions, one of the features you should pay attention to is the GMT function. Learn about the appeal and operation of GMT models and create a sophisticated adult look when doing business with overseas bases or traveling abroad. We also introduce five recommended models.
What is the GMT function on a wristwatch?
There is a category of wristwatches called GMT models. This article explains the overview and operation of GMT functions that display second and third time zones.
GMT function overview
GMT (Greenwich Mean Time), established by the International Meridian Conference in 1884, is the time at the Greenwich Observatory in London, England (longitude 0 degrees), that is, the reference time on the prime meridian.
GMT was formerly the world standard time, but since 1972 the world's time zones have been determined by UTC (Coordinated Universal Time), which is based on atomic clocks.
The GMT function allows the time in two different time zones to be displayed simultaneously. A typical GMT model can simultaneously display the local time indicated by the hour, minute, and second hands, and the home time indicated by the GMT hand, which rotates once every 24 hours.
Since the Rolex GMT-Master, the world's first GMT model, was released in 1955, it has become customary to refer to the second time zone display function as the GMT function even after the UTC was established, but brands such as IWC and Sinn call it the UTC function.
How to operate the GMT function
The operation method varies depending on the GMT model, but basically, you operate the hour and minute hands, GMT hand, and rotating bezel to read the time in the second or third time zone on the 24-hour display on the rotating bezel or inner bezel.
In the case of the Rolex GMT-Master II, you first set the rotating bezel in the neutral position (0 o'clock is at 12 o'clock), then set the home time and then the local time.
Pull the crown out two notches to operate the GMT and minute hands, then align the GMT hand with the scale on the rotating bezel and the minute hand with the scale on the dial to set the local time. Next, pull the crown back out one notch and operate the hour hand to set the local time and date.
Furthermore, by manipulating the rotating bezel, it is possible to read the third time zone from the time indicated by the GMT hand on the rotating bezel.
Tips for choosing a watch with a GMT function
Many fashion houses have released GMT models, with a wide variety of designs and sizes. To help you find your favorite GMT model from the wide range of options, we will explain two tips for choosing.
Check the visibility of the dial
GMT models carry more information than regular watches, so the visibility of the dial is important for everyday use. Check the thickness and color of the GMT hand and choose one that makes it easy to instantly read the current time.
The color combination of the dial and rotating bezel is also important. If you don't use the GMT function often, you'll be focusing on reading the hour and minute hands, so you'll want to make sure the rotating bezel isn't too noticeable and that it's easy to focus on the dial.
Choose the right size model for you
The size of a watch that fits you best will depend on the thickness of your wrist, the size of your hand, and your build. GMT models with rotating bezels in particular tend to look large, so while it depends on your personal preference, if you're concerned about balance, you'll want to pay attention to the size.
A good guideline for a balanced case diameter is 37mm or less for a slender person, and 38-42mm for a standard build. GMT models with a case diameter of 43mm or more give a bulky impression, so they are suitable for larger or muscular people.
5 Recommended Models with GMT Functions
Rolex is famous for its GMT models, but Rolex's sister brand, Tudor, also releases its own unique GMT models. Japan's proud watch brands, Grand Seiko and Citizen, also offer excellent GMT models. Here are five recommended GMT models.
Rolex "GMT-Master II" Ref. 126710BLNR
Automatic winding (Cal. 3285). 31 jewels. 28,800 vph. Power reserve approximately 70 hours. Oystersteel case (40mm diameter). Water resistant to 100m.
The Rolex GMT-Master II 116710BLNR, released in 2013, is the original model known as the "Batman," featuring a new blue-black bezel on the GMT-Master.
With the release of its successor, the 126710BLNR, in 2019, this model has become outdated, but the new model features a seven-link Jubilee bracelet, while the 116710BLNR, equipped with the traditional three-link Oyster bracelet, remains highly popular.
Rolex "GMT-Master II" Ref. 126719BLRO
Automatic winding (Cal. 3285). 31 jewels. 28,800 vph. Power reserve approximately 70 hours. 18KWG case (diameter 40mm). Water resistant to 100m.
The white gold model of the Rolex GMT-Master II, Ref. 126719BLRO, was released in 2019. It is an iconic piece featuring the red and blue bezel that is most characteristic of the GMT-Master.
In addition to the blue dial model above, the lineup also includes a model with a meteorite dial, which is made from a real meteorite. The only GMT-Master II with a meteorite dial is the ref. 126719BLRO.
Tudor Black Bay GMT
Automatic movement (Cal. MT5652). 28 jewels. 28,800 vph. Power reserve approximately 70 hours. Stainless steel case (diameter 41mm, thickness 14.52mm). 200m water resistant. 443,300 yen (tax included). (Inquiries) Rolex Japan / Tudor Tel. 0120-929-570
The Tudor Heritage Black Bay GMT 79830RB is a GMT model with a vintage-style red and blue bezel and a black dial, and no crown guards.
The slender font Arabic numerals on the bezel, the finely-cut coin edge, and the snowflake hands on the hour, second, and GMT hands all create a sophisticated, new classic look.
Tudor has been gaining popularity in recent years, partly due to its sponsorship of the Rugby World Cup. In 2021, the brand's flagship store in Ginza was relocated and reopened as "TUDOR BOUTIQUE BOLTE GINZA," which also includes an e-boutique function, further enhancing its status.
Grand Seiko "Elegance Collection Spring Drive GMT"
Automatic Spring Drive (Cal. 9R66). 30 jewels. Power reserve approximately 72 hours. Stainless steel case (diameter 40.2 mm, thickness 14.0 mm). Water resistant for everyday use. 891,000 yen (tax included). (Inquiries) Seiko Watch Customer Service (Grand Seiko) Tel. 0120-302-617
Grand Seiko's "Elegance Collection Spring Drive GMT" SBGE271 is a GMT model that uses Grand Seiko's proprietary "Spring Drive" movement. It does not have a rotating bezel, and the home time is displayed on a 24-hour display around the outer edge of the dial.
The case, hands, and indexes have an edgy design and finish, and the black dial represents the night sky of "Kanro," the fifth autumn solar term. The gold-colored GMT hand shines beautifully like moonlight peeking through herring clouds. The sweeping movement of the hands, unique to Spring Drive models, is also an appealing feature.
Grand Seiko is now popular not only in Japan but also overseas, and models equipped with GMT functions are in high demand as they are suitable for business situations.
Citizen "Citizen Series Eight 880 Mechanical"
Automatic winding (Cal. 9054). 24 jewels. 28,800 vph. Power reserve approximately 50 hours. Stainless steel case (diameter 41mm, thickness 13.5mm). 10 bar water resistance. 220,000 yen (tax included). (Inquiries) Citizen Customer Watch Consultation Center Tel. 0120-78-4807
Citizen launched the Series Eight in 2021 as a brand equipped with a mechanical movement. This marks a relaunch of the brand, as the company also had a brand of the same name in the 2000s.
The 880 Mechanical is a mechanical GMT model that was added to the brand in 2023. The edgy case, with its integrated lugs and bracelet, evokes the feel of luxury sports watches, which have now become a major genre in the watch market. At the same time, the blue dial with a checkered pattern and the coloring that incorporates blue, red, and orange are full of originality.
The movement, Cal. 9054, is equipped with second-class magnetic resistance, making this a GMT watch that is easy to use in today's world where magnetism is rampant.
Wear a GMT-equipped watch and take yourself to the next level
When moving from a simple three-hand model to one with additional functions, one of the features you should pay attention to is the GMT function, which allows you to check the time smartly when doing business with overseas bases or traveling abroad.
If you think a rotating bezel is a bit too flashy, there are also GMT models that allow you to read the home time on the outer edge of the dial or on the inner bezel. Wearing a GMT model will elevate you to the next level.
