KULUZE Ocean Series Diver Mechanics Watch Japan MIYOTA Automatic movement(21Jewels，8218 ), Designed for accuracy. Stainless steel case 45mm diameter x 16mm thick;Synthetic Sapphire crystal; Screw-down crown;Unidirectional Rotate Stainless steel circle;Ceramics bezel;Luminous Coating (need to absorb light energy storage). Grade 5 Titanium watch band, 220mm L x 24mm; Band is adjustable by adding/removing links; Fold over safety clasp. 300meter water resistant；with Automatic Helium Valve at 9H；Suitable for professional marine activity and surface water sports. Suitable for diving. Please screw tight the crown before go into water. Professional diving standard 5mm thick Sapphire Crystal；With Anti-reflective under coating；DS double safety technology, in order to prevent excessive pressure, the built-in metal snap ring is used to clamp the glass.