Seiko Prospex Spb503 Alpinist Turquoise Dial Case/Band Case Material: Stainless steel (super hard coating) Case Size:Thickness:12.7mm Diameter:39.5mm Lug-to-lug:46.4mmCrystal: Sapphire crystal with magnifier Crystal Coating: Anti-reflective coating on inner surface LumiBrite: Lumibrite on hands and index(es)Clasp: Three-fold clasp with push button release Distance between lugs: 20mmMovement Caliber Number: 6R55 Movement Type: Automatic with manual winding Precision: +25 to -15 seconds per day Power reserve: Approx. 72 hours(3 days) Jewels: 24 Functions: Stop second hand function Other Details Water Resistance: 20 bar Magnetic Resistance: 4,800 A/m Weight: 88.0g Features: Rotating compass bezelScrew-down crownSee-through & Screw case back