This Sports design with 18k yellow gold and ceramic accents is powered by the highly accurate 9R86 Spring Drive movement – precise to ±15 seconds a month, or ±1 second a day and the 72 hour power reserve is maintained even if the chronograph is in operation. Spring Drive is one of the most significant developments in recent watchmaking which took 28 years to develop.With a superior level of precision, Spring Drive generates energy with a mainspring combined with an electronic regulator, never requiring a battery change. Seiko Watch Corporation pioneered Spring Drive which is only available in their timepieces. Every Grand Seiko features signature high standards of Japanese precision, durability and legibility, handcrafted by Takumi artisans.Grand Seiko: beautifully, precise Japanese watchmaking, from the pinnacle of Seiko Watch Corporation’s in-house ‘manufacture.’