Rolex Datejust II watch, polished round stainless steel case (41mm diameter, 11mm thickness) with 18kt yellow gold screw-down Triplock winding crown, polished fluted 18kt yellow gold bezel, stainless steel and 18kt yellow gold Oyster bracelet with solid links and clasp, champagne dial with ten diamond index markers, date calendar at 3 o'clock, 31 jewel Caliber 3136 self-winding mechanical Oyster Perpetual COSC certified chronometer movement, scratch-resistant sapphire crystal, water-resistant to 100 meters (330 feet). Introduced in 1945, the Oyster Perpetual Datejust was the first wristwatch to feature a date display, clearly visible with a special magnifying Cyclops lens. The most popular of all the Rolex models, the Datejust is fashioned in steel, gold, platinum, or a combination of steel and gold (rose or yellow). This fine and elegant timepiece shows the wearer the time and the date of the month only, hence the name Datejust. Most models of the Rolex Datejust watch come in a variety of bezels, jeweled, smooth, or fluted. The hour markers are also very definitive in their make, ranging from single strips, Arabic or Roman numerals, to that of diamond-set studs. The hour and minute hands are typically luminescent (glow in the dark), which together with a smooth sweeping second hand is backed by a certified Swiss chronometer self-winding perpetual movement with 31 jewels. The Rolex Datejust also features solid Twinlock winding crowns (which screw down to enhance water resistance), minute calibrated dials, and magnifier over the date for easier reading. The crystal is made from synthetic sapphire (second hardest substance next to diamond), which provides scratch-resistance, and a lifetime of use and pleasure. And, authentic Rolex Datejust watch cases are forged from a solid block of metal, which further enhances water resistance.