Rolex Sky-Dweller 18kt Yellow Gold "Oysterflex", Saros Annual Calendar with Dual Timezone, Jet Black Index Dial with Highly Legible Chromalight Display with Long-Lasting Blue Luminescence Hands, Fluted Bidirectional Rotatable Rolex "Ring Command" Bezel, Screw-Down Crown with Twinlock Double Waterproofness System, Superlative Chronometer Rolex Manufacture Caliber 9001 Self-Winding Movement with Paramagnetic Blue Parachrom Hairspring and High-Performance Paraflex Shock Absorbers, Black Rubber Oysterflex Strap, Yellow Gold Deployant Buckle, 42mm

The solid 18kt Yellow Gold three-body case, gently curved lugs, buckle, and fluted bezel are polished/brushed. The dial is black with applied faceted luminous baton hour markers, gold skeleton baton hands with luminous inlays, and a gold center sweep second hand. There is a black perimeter minute/seconds track with 12 recessed square aperture windows for the Saros annual calendar, with recessed rectangles that turn red to show the corresponding month. An inner silver reserve with black Arabic numerals measures the GMT 24-hour time zone, and there is a red triangle indicator at 12 o’clock. There is a rapid-set date aperture window underneath a magnified Cyclops lens at 3 o’clock. It has a 72-hour power reserve at full wind, and it’s water resistant to 100 meters/330 feet. It has a Certified Official Superlative Chronometer (COSC) rating, and the 14.5mm thick case, dial, and movement are all signed. 

This Rolex Sky-Dweller 326238 has a mechanical automatic self-winding Rolex caliber 9001 movement that’s rhodium-plated, and it’s constructed with 40 jewels, a straight-line lever escapement, and a shock absorber mechanism. It has bi-directional self-winding via a perpetual rotor. There is a monometallic balance that’s adjusted to 5 positions, and a free-sprung self-compensating Breguet balance spring. It includes a paramagnetic blue Parachrom hairspring, Microstella regulating screws, and a central hacking mechanism. The rotor oscillates at a frequency of 28,800 vph (4 Hz). It’s based on a mechanism called SAROS - after the Greek term for the 18-year cycle of the sun, earth, and moon that registers both lunar and solar eclipses. Two gear ratios and four gear wheels were added to the traditional Rolex date calendar to make it a full annual calendar, only requiring re-setting once a year at the end of February.

Reference No. 326238