Seiko NH34 GMT automatic movement
All about the essential GMT caliber
The GMT (Greenwich Mean Time) complication is one of the most sought-after watch functions by travelers and enthusiasts of fine mechanics. Allowing simultaneous tracking of time in two distinct time zones, it has become widely democratized thanks to a Japanese caliber renowned for its precision and endurance: the Seiko NH34 automatic movement (produced by TMI, a subsidiary of Seiko Instruments Inc.).
At the heart of our brand new Concordia GMT, this movement combines industrial reliability with everyday precision to accompany modern explorations.
What is the Seiko NH34 caliber?
Derived from the famous NH35 and NH36 calibers, the NH34A is a mechanical self-winding movement specially designed to accommodate a fourth central hand dedicated to the 24-hour cycle.
- Origin: Japan (TMI / Seiko Group)
- Movement type: Mechanical automatic winding
- Complications: Hour, Minute, Second, Date, GMT Hand (24h)
- Frequency: 21,600 alt/h (3 Hz)
- Power Reserve: ~41 hours
- Number of Jewels: 24 jewels
- Luminescence: Super-LumiNova® (Swiss RC Tritec)
- Functions: Stop-seconds and manual winding
How does the "Office GMT" complication work?
The NH34 caliber adopts an "Office GMT" (or Caller GMT) architecture. This system prioritizes the direct and independent setting of the 24-hour hand without stopping the watch's movement.
- Quick adjustment of the date in one direction of rotation.
- Advancing the GMT hand hour by hour in the other direction.
This is the ideal configuration for keeping an eye on a distant time zone, planning an international call, or tracking the time of a loved one abroad with a quick glance at the 24h rehaut.
The new Concordia GMT: the reinvented tool watch
To accommodate this caliber, we have completely redesigned the architecture of our iconic model. The Concordia GMT retains its adventurer DNA while gaining in refinement and technicality:
- 30 ATM (300 m) water resistance: A robust 40.5 mm (11.75 mm thick excluding glass) 316L steel case with a screwed-down crown.
- Double-domed sapphire crystal: Anti-reflective treatment for unique visual depth, complemented on the back by a transparent sapphire case back allowing admiration of the mechanism.
- Optimal legibility: New raised indices, rehaut dedicated to the minute track, and Swiss Super-LumiNova® (RC Tritec) luminescent treatment.
5 colors inspired by the great outdoors
The collection revolves around five shades designed for every temperament:
- Antarctic Blue: A tribute to the model's origins, originally designed for Matthieu Tordeur's polar expedition to Antarctica (1,150 km at -37 °C).
- Black: The technical and timeless elegance of the benchmark tool watch.
- Tundra: A luminous white dial evoking frosty landscapes.
- Bordeaux: An assertive and warm temperament.
- Sage: A subtle and contemporary botanical shade.
All versions benefit from our tool-free quick-change strap system (standard 20 mm lug width), allowing you to switch in seconds between workshop leather, technical material, and our new stainless steel bracelet.
The Concordia GMT reconciles Japanese precision with the demands of French watch design.
