What a GMT bezel is actually doing
A Seiko mod is a watch built around a genuine Seiko movement, with the case, dial, hands, bezel and crystal specified rather than inherited. On a GMT that movement is a genuine Seiko NH34 automatic.
The NH34 is a true GMT. There is a fourth hand that goes around once every 24 hours instead of once every 12, and it is independently adjustable. Set the main hands to where you are. Set the 24-hour hand to where you are not. Read the second zone off the bezel.
That independence is genuinely unusual at this price. Plenty of watches with GMT on the dial run a 24-hour hand geared to the hour hand, so it cannot show you anything the main hands are not already showing. That is decoration. This is a function. We went through the detail here.
Because the bezel covers a full day rather than half of one, it gets split in two: daylight hours and night hours. Two halves means two colours. Two colours is how a watch complication ended up named after soft drinks.
Where the names came from
Red and blue on one bezel. Somebody decided that looked like a can of Pepsi, said it out loud, and the name outlived every alternative anyone tried. Red and black became the Coke. Green and black became the Sprite, much later and with considerably more arguing.
Like every watch nickname, none of it was ever official. No manufacturer printed Pepsi on anything. The names survived because they are useful. "Two-tone 24-hour bezel in red and blue" is accurate and nobody says it. "Pepsi" is two syllables and everyone knows what you mean, including the shops selling them.
Pepsi: red and blue
The original, and still the one most people picture when they hear GMT.
Red for the daylight half, blue for the night half. It is the most legible of the three, because red and blue sit far apart in tone as well as in colour. The split between day and night is obvious at arm's length. On a watch whose entire job is being read quickly while you are tired in an airport, that is not a small thing.
It is also the loudest. A red and blue bezel is a colour statement whether or not you intended one, and it will be the thing people notice about your wrist. Fine if you own other watches. Worth knowing if this is going to be your only one.
Buy the Pepsi if you want the reference version of this watch. Most recognised, and the one that reads instantly as a travel watch rather than a diver with an extra hand.
GMT (Pepsi), A$399.
Coke: red and black
The sleeper. Every range has one and this is ours.
Same red for daylight, black instead of blue for night. What that swap does is turn a colourful watch into a mostly black watch with a red accent, and the change in character is much larger than the change in specification suggests. The Pepsi announces itself. The Coke lets you decide when it does.
The practical case is straightforward. Black goes with everything you own, and it does not date. If you are buying one watch to wear five days a week, this is the one that will still feel right in the third year.
The trade is small. Red against black is marginally less distinct in low light than red against blue, because both halves are dark. In practice you learn your own bezel inside a week.
Buy the Coke if you want the function without the announcement. It is the one we end up recommending most often to people buying their first GMT.
GMT (Coke), A$399.
Sprite: green and black
The newest of the three, and the most divisive.
Green for daylight, black for night. Green on a 24-hour bezel is a recent idea and it still splits opinion in a way the other two do not. People either want it specifically or dismiss it outright. Very little middle ground, and we see that in what gets ordered.
The green is the whole decision. Vivid rather than olive, so in daylight it is the brightest thing on the watch by a distance. Under a desk lamp it closes down toward black and the bezel reads almost monochrome. That range is either the appeal or the problem, depending entirely on who you are.
Buy the Sprite if you already own a conventional GMT, or if you looked at the Pepsi and found it too familiar. Do not buy it as a safe first choice, because it is not one, and we would rather say so than sell you the wrong watch.
If it is the green you like rather than the GMT, we build that idea on divers too. The Hulk and the Kermit.
GMT (Sprite), A$399.
Which one you actually want
The short version.
- Pepsi if you want the definitive one and you are happy for the watch to be noticed.
- Coke if it is going to be your daily watch and you want it to go with everything.
- Sprite if you want the one nobody else at the table is wearing, and you already know you like green.
If you cannot decide between the Pepsi and the Coke, buy the Coke. A watch you wear every day beats a watch you admire on a Saturday.
The three that are not soft drinks
The other half of the range answers the same question differently.
Batman is blue and black. The two-tone split without any red in it, and the quietest of the colourful ones.
Bruce Wayne is all black, bezel included. No day and night split at all, so you give up some at-a-glance reading and gain a watch that looks like nothing else here. We covered what to check on it here.
Root Beer is brown and gold, and it is the one people skip first and then come back to. Warm and dressy where every other bezel here is sporty, with the most loyal owners in the collection. We gave it its own article.
What is inside, on all six
The colourway is the only decision you are making. Everything behind it is identical.
Genuine Seiko NH34 automatic with a true independent GMT hand: self winding, hand windable, and it hacks so you can set it to the second. 40 mm 316L stainless steel case. Sapphire crystal, which resists the scratches ordinary glass picks up. 1 year warranty, handled in Australia.
50 m (5 ATM), which covers rain and hand washing. It is not a swimming watch and we are not going to imply it is. Here is what that rating actually means. The rotating bezel is there because the design was drawn that way, not because the rating supports taking it under.
A$399 across the range. Built to order in about 2 to 3 weeks, then shipped free worldwide.
At 40 mm these wear as the design intends. A GMT bezel is printed rather than blank, so the eye reads it as busier than a plain diver bezel and the watch presents slightly larger than the number suggests. Under about 17 cm of wrist it still goes under a cuff.
These are homages, not copies. No other brand's name on the dial. That distinction matters. The wider case for a dual-time watch at this money is here.
Made to be looked at twice.
Browse the whole GMT range · See the GMT (Pepsi) · See the GMT (Coke) · See the GMT (Sprite) · Read the Root Beer article
Sources
Primary references for the technical and regulatory claims above.
- Time Module NH34 calibre listing - the independently adjustable GMT hand specification.
- Time Module (Seiko Instruments) NH-series product line-up - manufacturer specifications for the NH-series calibres.