Exterior: Stainless steel Case back: See-through & Screw case back Glass Material: Dual-curved sapphire crystal Glass Coating: Anti-reflective coating on inner surface Case size: Diameter 41.0mm Lug-to-lug 49.0mm Thickness 12.5mm Band width: 20mm Clasp type: Three-fold clasp with push button release The perimeter of Band: 195mm Movement Caliber no.: 9R65 Instructions 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 Weight: 150 g Other details / Features: Screw-down crown 30 jewels Power reserve indicator