Reference: 116503. MODEL CASE: Oyster, 40 mm, Oystersteel and yellow gold. OYSTER ARCHITECTURE: Monobloc middle case, screw-down case back and winding crown. DIAMETER: 40 mm. MATERIAL: Yellow Rolesor – combination of Oystersteel and 18 ct yellow gold. BEZEL: Fixed, with engraved tachymetric scale, in 18 ct yellow gold. WINDING CROWN: Screw-down, Triplock triple waterproofness system. CRYSTAL: Scratch-resistant sapphire. WATER-RESISTANCE: Waterproof to 100 metres / 330 feet. MOVEMENT: Perpetual, mechanical chronograph, self-winding. CALIBRE: 4130, Manufacture Rolex. PRECISION: -2/+2 sec/day, after casing. FUNCTIONS: Centre hour, minute and seconds hands, small seconds hand at 6 o’clock. Chronograph (centre hand) accurate to within 1/8 of a second, 30-minute counter at 3 o’clock and 12-hour counter at 9 o’clock. Stop seconds for precise time setting. OSCILLATOR: Paramagnetic blue Parachrom hairspring. WINDING: Bidirectional self-winding via Perpetual rotor. POWER RESERVE: Approximately 72 hours. BRACELET: Oyster, flat three-piece links. BRACELET MATERIAL: Yellow Rolesor – combination of Oystersteel and 18 ct yellow gold. CLASP: Folding Oysterlock safety clasp with Easylink 5 mm comfort extension link. DIAL: Black. DETAILS: Dial with snailed small counters.