Rolex Sky-Dweller Oystersteel ’Black’ Saros Annual Calendar 904L Stainless Steel with Monobloc Middle Case, Black Dial with Chromalight Display Index Hour Markers with Long-Lasting Blue Luminescence, 904L Stainless Steel Oyster Bracelet with Easylink 5mm Comfort Extension Link 42mm

The 42mm diameter solid three-body case, straight lugs, bracelet, and fluted bezel are polished/brushed. The dial is black with applied faceted luminous baton hour markers, polished skeleton hands with luminous inlays, and a polished steel center sweep second hand. There is a luminous outer 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 bright reserve with white 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 Oystersteel ’White’ Saros Annual Calendar has an integral 904L Stainless Steel bracelet with a folding deployment clasp, and a scratch resistant sapphire crystal. It has the rotatable fluted 18k white gold "Ring Command" bezel that can be set to three functions, including date, local time or a GMT reference time, utilizing the winding crown. It has a solid screw-down case back and the Twinlock double water-resistant Rolex winding crown. 

This Rolex Sky-Dweller Oystersteel ’Black’ Saros Annual Calendar has a mechanical automatic self-winding Rolex caliber movement. It’s rhodium plated, with 380 components, a Paramagnetic blue Parachrom hairspring with a Breguet overcoil, and high-performance Paraflex shock absorbers. It has a traversing balance bridge, and a large balance wheel with variable inertia and four gold Microstella nuts. The mechanism oscillates at a frequency of 28,800 vph (4 Hz).

This watch is one of the most complex watches ever produced by the company. The “Saros” annual calendar made in house by Rolex, automatically differentiates between 30-day and 31-day months. It displays the correct date and requires only one adjustment a year on March 1st.