Evolution 9 Spring Drive U.F.A. Ushio 300 Diver SLGB023

In 2025, Grand Seiko unveiled the Spring Drive Caliber 9RB2, a groundbreaking movement that received the then-new U.F.A. designation, standing for “Ultra Fine Accuracy.” Boasting an annual accuracy rate of ±20 seconds, Caliber 9RB2 earned the distinction of being the most accurate wristwatch movement powered by a mainspring.* This model is powered by Caliber 9RB1, featuring an improved construction that makes it ideal for sporting conditions while sharing the same attributes as the Caliber 9RB2. The term ushio, which means “tide” in Japanese, evokes the waters that surround the Japanese archipelago. This creation’s blue dial reflects the vast expanse of the sea through a gradient that captures light streaming into the deep ocean. * As of April 2026, based on Grand Seiko’s research. Exterior Exterior: High-Intensity Titanium Case back: Screw case back Glass Material: Sapphire crystal Glass Coating: Anti-reflective coating on inner surface LumiBrite: LumiBrite on hands, index(es) and bezel Case size: Diameter 40.8mm Lug-to-lug 48.5mm Thickness 12.9mm Band width: 21mm Clasp type: Locking extension clasp with micro-adjustment The perimeter of Band:195mm Movement Caliber no.: 9RB1 Instructions Movement Type: Spring Drive Power reserve: Approx. 72 hours(3 days) Accuracy: ±20 seconds per year (±3 seconds per month) Functions Water resistance: 300m / 1000ft diver's Magnetic resistance: 4,800 A/m Weight: 122 g Other details / Features: Unidirectional rotating bezel Screw-down crown Allergy-safe metal 33 jewels Power reserve indicator