The Rolex Datejust reference 1601 is an iconic vintage timepiece produced from approximately 1959 to 1981. It is characterized by its 36mm Oyster case, a fluted bezel (typically in white or yellow gold), and an acrylic crystal with the Cyclops magnifying lens for the date. One of the signature features of many 1601 models is the "pie-pan" dial, which has a stepped, downward-sloping outer edge. It was initially powered by the automatic caliber 1565, which was later updated to the 1575. Available in a variety of materials including stainless steel, yellow gold, and two-tone (Rolesor) versions, the 1601 is regarded as a timeless classic and an excellent entry point for vintage Rolex collectors.