316L Surgical-Quality Stainless Steel Case Jeweled 2560 Automatic Movement Jewel Bearings: 22 Jewels 41 Hour Power Reserve Beats per Hour (BPH): 21600/Hour Sapphire-Coated Mineral Crystal Observation Case back to view Movement Uni-Directional Bezel Screw-Down Crown Logo-Engraved Stainless Steel Clasp Luminous Hands Luminous Markers Date Display 41mm Case Diameter 20 ATM (Professional Diver Water Resistance)