The Rolex Cosmograph Daytona reference 16523 is a highly sought-after "Zenith" Daytona model, produced from 1988 to 1999. It features a 40mm case crafted from a two-tone combination of stainless steel and 18k yellow gold, known as Rolesor. This model is powered by the Rolex Caliber 4030, an automatic chronograph movement based on the renowned Zenith El Primero caliber, which Rolex extensively modified to meet its stringent standards. It is fitted with a matching two-tone Oyster bracelet and is water-resistant to 100 meters. The dial was available in various colors, including white, black, and champagne, often with contrasting sub-dials, contributing to its distinctive and timeless appeal.