The first ever Grand Seiko chronograph, this model is powered by a Grand Seiko’s unique Spring Drive caliber, which combines the motive force of a mainspring with the high precision of a quartz watch.
The Spring Drive mechanism allows the watch to maintain precise timekeeping while also incorporating accurate chronograph capabilities, all with a maximum 72-hour (3-day) power reserve.
Grand Seiko's original glide motion is also featured in the chronograph's blue steel second hand.
The chronograph utilizes a Ready/Start button with a half-press shutter, reducing mistakes and allowing for accurate starts. The button has been designed with comfort of use in mind and produces a satisfying click with just the right resistance.
Exterior: Stainless steel case back: stainless steel and sapphire glass
Back cover: Screw see-through back cover
Glass material: dual curve sapphire
Coating: Inner non-reflective coating
Case size: Width 43.5mm Length 51.2mm Thickness 16.1mm
Clasp: One-push three-fold method
Arm circumference length (longest): 201mm
Driving method: Spring drive automatic winding (with manual winding)
Drive period: About 72 hours (about 3 days) at maximum winding
Accuracy: Average monthly difference ±15 seconds (equivalent to daily difference ±1 second)
Waterproofing: Reinforced waterproof for everyday life (10 bar)
Antimagnetic: can be
Other: ・50 koku ・24-hour hand (dual time display function)
・Stopwatch function (30 minutes total, 12 hours total)
・Power reserve display function ・Calendar interlocking time difference correction function ・Screw lock type crown