Grand Seiko caliber 9S64
Caliber 9S64 is is a mechanical hand-wound movement introduced in 2011. It delivers a 3-day power reserve, thanks to the use of a thinner and longer mainspring made of SEIKO’s proprietary alloy “SPRON510”. In addition, the balance spring is made of another recently developed highly shock resistant and anti-magnetic alloy “SPRON610” and the caliber uses a new escape wheel and pallet manufactured by MEMS. These new components contribute to its reliable and precise performance; its timekeeping precision is -3 to +5 seconds per day, a level that is confirmed in every case by testing to the very exacting Grand Seiko standard, the highest published standard in the industry.