GRAND SEIKO SPRING DRIVE GMT

GRAND SEIKO Spring Drive GMT Reference: SBGE201.

Self-winding mechanical watch Calibre 9R66 with 72-hour power reserve, 30 jewels. Steel case 41 mm in diameter with steel bracelet with steel Grand Seiko folding clasp.

Black dial with power reserve indication at 7 o'clock and date window at 3 o'clock, GMT indication by means of the central red hand and hours on the flange.



Antiglare sapphire crystal and sapphire caseback revealing the movement, water-resistant to 100 meters.

Collector's watch no longer in the Grand Seiko catalog with polishing available on request.

Watch with 2-year warranty.

Like all other mechanical watches, the Spring Drive movement is driven by a mainspring. This traditional way of generating power allows the watch to be completely self-sufficient, without the need for a battery or other power source.

The mainspring is wound by turning the crown or moving the wrist, in order to accumulate energy, which is then transferred to the gears and used to move the watch hands as the spring unwinds.

By taking advantage of the high torque offered by the mainspring, the movement needs no other source of energy to move the long, wide hands, emblematic of Spring Drive, smoothly.

Spring Drive uses an exclusive speed control mechanism that includes an integrated circuit, an electronic brake and a quartz crystal.

Without a mechanism to adjust the speed at which the mainspring disarms, it would unwind rapidly and the watch would stop suddenly. To achieve accurate timekeeping, a mainspring control mechanism is required.

The tri-synchro regulator developed by Seiko performs this function.

As its name suggests, the tri-synchro regulator uses three types of energy to regulate moving parts and ensure synchronization:

Mechanical energy, produced by the mainspring
Electrical energy, creating a reference signal via an integrated circuit and quartz oscillator.
Electromagnetic energy, to apply a brake using a rotor and stator.

These three forces work in harmony, to regulate the spring and enable the precise movement of the seconds hand.