The Grand Seiko SBGA031 features a 44.2mm high-intensity titanium alloy case and bracelet exclusive to Seiko. This titanium is not only light weight, but also corrosion resistant and capable of achieving the mirror finishing technique known in Japan as Zaratsu, a method used for polishing katana blades. These attributes along with Seiko's Spring Drive technology in the exclusive Grand Seiko 9R65 caliber add up to the perfect recreational diver expressed in the SBGA031. The 9R65 found in the SBGA031 is rated to +/- 15 seconds per month, using an electro-magnetic braking system to control the unwinding of the mainspring, creating a completely smooth gliding motion that can only be found in Spring Drive. This also boasts a 72 hour power reserve with a display of power shown on the dial. This diver uses Lumi-Brite, another proprietary Seiko product, for unbelievable night time legibility, or when diving in the darkest waters. The SBGA031 also has a ratcheting expansion clasp, making it suitable to fit over a wet suit when needed.
Drive system Spring Drive Caliber No. 9R65 Case High-intensity titanium Bezel High-intensity titanium and black hard-coated high-intensity titanium Case back Screw case back Glass Sapphire crystal with anti-reflective coating Bracelet Solid high-intensity titanium and solid titanium Buckle Titanium and stainless steel with three-hold clasp with secure lock, push button release and diver adjuster Accuracy ±1 second / day Water resistance 200 m Magnetic resistance 4800 A/m (60 gauss) Weight 137g Case thickness 14.0mm Case diameter 44.2mm Jewels 30 Remarks One-way rotating bezel Screw crown