Grand Seiko Heritage Watch SBGA439G A moonlit sky at night has a tantalizing and ever-changing hue which is captured perfectly in this midnight blue dial. Sometimes, the warmth of the blue is to the fore and, at others, the dial seems almost pitch black. Whatever its aspect, this dial is the perfect backdrop against which the diamond-cut hands and hour markers stand out in sharp relief. Exterior Exterior: Stainless steel Case back: Screw case back Glass Material: Dual-curved sapphire crystal Glass Coating: Anti-reflective coating on inner surface Case size: Diameter 40.0mm Lug-to-lug 46.6mm Thickness 12.3mm Band width: 20mm Clasp type: Three-fold clasp with push button release The perimeter of Band: 203mm Movement Caliber no.: 9R65 Movement Type: Spring Drive Power reserve: Approx. 72 hours(3 days) Accuracy: ±15 seconds per month (±1 second per day) Functions Water resistance: 10 bar Magnetic resistance: 4,800 A/m Other details / Features: Screw-down crown 30 jewels Power reserve indicator