Black PVD stainless steel case and bracelet. Uni-directional rotating black PVD bezel. Black dial with luminous hands and index hour markers. Minute markers. Tachymeter around the outer rim. Dial Type: Analog. Luminescent hands and markers. Day of the week and date display at the 3 o’clock position. Chronograph – three sub-dials displaying: 60 second, 30 minute and 12 hour. Automatic movement with a 44-hour power reserve. Scratch resistant sapphire crystal. Screw down crown. Solid case back. Case diameter: 42 mm. Case thickness: 15 mm. Round case shape. Fold over clasp. Water resistant at 200 meters / 660 feet. Functions: chronograph, day, date, hour, minute, second. Sport watch style. Watch label: Swiss Made. Item Variations: 638 18 31 M, 638-18-31 M, 638/18/31 M, 6381831 M. Fortis Official Cosmonauts Automatic Choronograph Black Dial Black PVD Mens Watch 6381831M.