Grand Seiko SBGM245vsSpinnaker Dumas GMT
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Measurements
Catalog photos are all shot at the same flattering size. These aren't: every case below shares one millimeter scale.

SBGM245

Dumas GMT
Diameter
40.5mm
44mm
Lug-to-Lug
48.6mm
48mm
lowest
Thickness
14.4mm
lowest
15mm
Water Resistance
200m
300m
highest
Power Reserve
72h
n/a
MSRP
$6,100
$399
lowest
Movement
Grand Seiko 9S66
Seiko NH34
Case
6 specsCrystal & Dial
2 specsMovement
2 specsPricing
1 specsReviews
Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.
Owners widely praise the Grand Seiko SBGM245 as a compelling mechanical GMT, blending sport and luxury with notable workmanship. Some owners find its 40.5mm case size and 14.4mm thickness wearable, while others consider it too large and prefer slimmer alternatives. The polished surfaces are noted to scratch easily, suggesting it is best suited for dressier occasions. Accuracy figures vary, with one owner reporting an average gain of two seconds per day, while others express a desire for a thinner case and a clasp with quick extension. Overall, owners rate the Grand Seiko SBGM245 highly for its mechanical GMT functionality and craftsmanship, despite some reservations about its size and scratch resistance.
The Spinnaker Dumas GMT is praised for its good finishing and satisfying lume, including on the crown. Owners note its 44mm case and 15mm thickness, with one finding it wears well on a 17cm wrist, while a reviewer suggests its substantial size and 209g weight make it unsuitable for smaller wrists. Overall, owners and reviewers find the Spinnaker Dumas GMT offers good value, particularly with the inclusion of an extra rubber strap.
The Spinnaker Dumas GMT offers robust build quality for its price point. Reviewers noted the 300-meter water resistance.
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