Housed in a 40mm Oyster case crafted from 18 kt white gold, reference 126509-0002 features a monobloc middle case, solid screw-down case back, and a screw-down winding crown secured by the Triplock triple waterproofness system. A fixed 18 kt white gold bezel carries an engraved tachymetric scale, while scratch-resistant sapphire crystal protects the dial beneath. Water resistance extends to 100 metres / 330 feet.
The bright black dial is set with diamonds in 18 kt gold settings and presents a Chromalight display with long-lasting blue luminescence for high legibility. Inside beats the Calibre 4131, a perpetual mechanical self-winding chronograph movement manufacture Rolex, rated to -2/+2 seconds per day after casing and COSC certified. The oscillator employs a paramagnetic blue Parachrom hairspring and Paraflex shock absorbers, with bidirectional winding via a Perpetual rotor and approximately 72 hours of power reserve.
Chronograph functions include a centre seconds hand, a 30-minute counter at 3 o'clock, and a 12-hour counter at 9 o'clock, alongside a stop-seconds mechanism for precise time setting. The watch is worn on an 18 kt white gold Oyster bracelet with three-piece solid links, secured by a folding Oysterlock safety clasp featuring an Easylink 5 mm comfort extension link.