TMI · Automatic caliber guide
One watch. A second time zone.
The NH34A adds a fourth central hand to track another time zone on a 24-hour scale. You adjust that GMT hand separately from the ordinary hour hand. It is a useful distinction to understand before choosing a watch for travel or keeping an eye on someone else’s working day.
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Published figures, with the context that makes them useful.
Specification reference: TMI — NH3 series technical guide (PDF). These are published specifications, not measurements from my own testing. All manufacturer sources ↓
My take
I would consider the NH34A for tracking home, a colleague, or another place while leaving the main hands on my everyday time. For frequent travel, I would try the setting routine before buying: being able to move the local-hour hand independently can be useful, and that is a different GMT arrangement.
Beyond the spec sheet
The GMT hand makes one circuit per day. Read it against the watch’s 24-hour scale: pointing to 18 means 6 p.m. in the time zone you assigned to that hand. The ordinary minute hand supplies the minutes. Check the watch’s bezel instructions if its 24-hour scale rotates.
At the second crown click, set the main hour and minute hands and check AM/PM. At the first click, TMI specifies turning the crown right to adjust the 24-hour hand, and left to correct the date. Push the crown home after setting, then secure it as the watch’s manual requires. [source]
TMI warns against quicksetting the date between 9 p.m. and 4 a.m. on the watch. Move the main hands outside that interval before correcting the calendar. Clockwise crown winding is available in the normal position; follow the finished watch’s instructions for its crown. [source]
Compare the tradeoffs
Useful comparisons for choosing a watch. These are not claims of parts compatibility.
The movement, in a watch
A selected starting list, grouped by brand. Each exact model below has a manufacturer source confirming the caliber.
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Reference P024-021-01
Minus-8 identifies NH34 GMT for the Diver GMT. This example is the black version, reference P024-021-01; the ordinary Diver 2.0 is a different model.
Reference SP-5157-44
Spinnaker specifies TMI NH34 for the Croft 39 GMT Mint Moment, reference SP-5157-44. My separate Pacific Pulse review covers another colorway.
Model and caliber checked October 14, 2026. Specifications and stock can change; confirm the exact reference with the seller. A manufacturer-verified example is not a hands-on review.
Quick answers
It is commonly called a caller GMT: the 24-hour hand adjusts independently. A traveler or flyer GMT instead lets you jump the ordinary local-hour hand separately. These are descriptions of the setting behavior, not accuracy or quality ratings.
No. You can set the extra hand to the time zone you want to follow. Read it on the 24-hour scale, where noon is 12 and midnight is 0 or 24. If a location changes its clocks seasonally, check whether your chosen offset needs correcting.
Treat that as a watchmaking compatibility question, not an automatic swap. The additional central hand needs suitable dial and hand fitment and enough clearance under the crystal. A matching movement diameter alone does not establish that the conversion will work.
Check the details
Movement specifications checked . Watch-specific evidence is linked with each example above. I keep manufacturer claims separate from my editorial assessment and any hands-on review.