Rolex Sky-Dweller 42 mm Black Dial — Key Specs  Feature Specification Model Name Rolex Sky-Dweller 42 mm (Black Dial) Reference 336933 Case Diameter 42 mm Case Material Rolesor (Oystersteel & 18 k Yellow Gold) Bezel Fluted, bidirectional Rolex Ring Command bezel in Yellow Gold Dial Color Black with luminous gold-tone hour markers Crystal Scratch-resistant sapphire with Cyclops lens over date Movement Rolex Calibre 9002 automatic, self-winding Functions Annual calendar (Saros), Dual time zone (GMT), Date, Month Power Reserve Approx. 72 hours Bracelet Oyster bracelet with Oystersteel & Yellow Gold links Clasp Folding Oysterclasp with Easylink 5 mm comfort extension Water Resistance 100 m / 330 ft Certification Rolex Superlative Chronometer (-2/ 2 sec/day) Style Category Luxury Travel / Annual Calendar Watch