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Seiko Caliber 9s66

Grand Seiko Caliber 9S66

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.

Grand Seiko 9S66

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Paul Hamilton
Paul Hamilton

This is my grail movement. It’s in a great watch, the power reserve is big, and that blue rotor is so nice.