Model case Oyster, 40 mm, platinum Oyster architecture Monobloc middle case, screw-down case back and winding crown Diameter 40 mm Material Platinum Bezel Chestnut brown monobloc Cerachrom bezel in ceramic with moulded numerals and graduations 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 4131, manufacture Rolex Precision -2/+2 sec/day, after casing Functions Centre hour and minute hands, small seconds hand at 6 o'clock. Chronograph via centre seconds hand, 30-minute counter at 3 o'clock and 12-hour counter at 9 o'clock. Stop seconds for exact time setting Oscillator Paramagnetic blue Parachrom hairspring. High-performance Paraflex shock absorbers Winding Bidirectional self-winding via Perpetual rotor Power reserve Approximately 72 hours Bracelet Oyster, three-piece solid links Material Platinum Clasp Folding Oysterlock safety clasp with Easylink 5 mm comfort extension link