Grand Seiko Caliber 9S66

Brand	Seiko
Caliber Number	9S66
Movement Type	Automatic
Jewels	35
Power Reserve	72 hours
Vibrations Per Hour	28,800
Hairspring	Spron 610
Shock System	Diashock
Features	GMT
Country of Manufacture	Japan
Known Models	SBGM031

The Seiko caliber 9S66 is an in-house movement found in a Grand Seiko GMT Limited Edition. This caliber is essentially an upgrade from GS cal. 9S56 which offered a lower 48 hr power reserve. The 9S66 found in the limited edition GMT has a blue titanium/tungsten rotor featuring a Grand Seiko lion crest.

Additional Resources:

• Read more: Official 9S66 operating instructions from Seiko
• Grand Seiko GMT Anniversary Limited Edition Review