Rolex GMT-Master II "50th Anniversary" 18kt Yellow Gold & Stainless Steel "Traveller" Dual Timezone with Oyster Architecture Monobloc Middle Case, Bidirectional Rotatable 24-Hour Graduated Bezel with Black Cerachrom Insert in Ceramic  with Engraved Numerals and Graduations, Black Dial with Luminescent Hour Markers and Hands, Greent GMT Hand, 18kt Yellow Gold Oysterlock Bracelet  with Easylink 5mm Comfort Extension Link, Screw-Down Crown with Triplock Triple Waterproofness System, Superlative Chronometer Rolex Manufacture Caliber Self-Winding Automatic Movement, 40mm - Fitted on a Gorgeous Bespoke Madrid Spain Green Rubber Strap

This Rolex GMT-Master II has a mechanical automatic winding caliber movement. It’s rhodium-plated, and it’s constructed with 25 jewels, a shock absorber mechanism, and a straight-line lever escapement. It has a monometallic balance adjusted to cold, heat, and 5 positions, and a self-compensating Breguet balance spring. It is equipped with a Rolex blue Parachrom hairspring made from a paramagnetic alloy including zirconium and niobium; it’s resistant to magnetic fields, temperature changes, and shock. The mechanism oscillates at a frequency of 28,800 mph (4 Hz).

Reference No. 116713LN