Self-winding mechanical movement Calibre Longines L688.4 beating at 28'800 vibrations per hour, with a monocrystalline silicon balance-spring power reserve of approximately 66 hours. Column Wheel Chronograph. Chronometer certified by the COSC. Round shape steel case, 42 mm diameter, 16.50 mm thickness. Scratch-resistant sapphire crystal, with several layers of anti-reflective coating on both sides. Water-resistant to 10 bar. Screw-in crown and screw-down steel case back. Sunray blue dial with applied Arabic numerals and silvered sandblasted hands. Central 60 seconds hand, 30 minutes counter at 3 o'clock and 12 hours counter at 6 o'clock. Date aperture between 4 and 5 o'clock. Original blue leather strap with steel pin-buckle.