Polished 18kt yellow gold case. Triplock crown & screw down chronograph buttons. Polished black Cerachrom (ceramic) bezel with engraved tachymeter scale. Bright black dial with golden sub-dials. Polished yellow gold hands, the hour & minute hands with partial luminous fill. 8 diamond hour markers. Applied 3,6 & 9 polished yellow gold index hour markers with luminous fill. Fine printed minutes/seconds & fractions of a second track. Small seconds sub-dial at 9 o'clock. Chronograph/Stopwatch function: Column wheel & vertical clutch mechanism. Large central seconds counter hand. 30 minute counter sub-dial at 3 o'clock. 12 hour counter sub-dial at 9 o'clock. Rolex in-house calibre 4131, beats at 28,800 vph (4Hz), contains 47 jewels & has a ower reserve of +/- 72 hours (3 days). Superlative Chronometer (COSC + Rolex certification after casing). Paramagnetic blue Parachrom hairspring. High performance Paraflex shock absorbers. Bidirectional self-winding rotor. AKA: m126518ln-0006