http://www.thewatchbox.com Among sports chronographs, this Rolex Cosmograph Daytona ref. 16519 is the gold standard... in 18-karat white gold. Forever linked with the annual Rolex 24 Hours of Daytona, the famed "Cosmograph" is a classic. Add the legendary Zenith "El Primero" chronograph movement to the equation, and you have a perfect storm of collectible charisma. Rolex built the El Primero-powered Rolex Cosmograph Daytona from 1988 until early 2000, and the model is revered by collectors for its rarity, durability, and pioneering role as the first "modern" Rolex Daytona. Before the 16520 Daytona (and the 16519 variant shown here), the Rolex Daytona was an oddball: too small, manually-wound, and widely considered to be ugly. All that changed with the El Primero-engined Cosmograph. Rolex redesigned the watch around a 40mm Oyster Case, and the El Primero added automatic winding to ensure ever ready power during epic races and office epics alike. For the first time, a scratch-resistant sapphire crystal replaced the old plastic unit. To this day, 40mm, automatic, sapphire, Oyster case remains the winning formula for racing's "winningest" watch. While the El Primero ranks among the greatest chronograph calibers of all time, the Rolex philosophy always calls for upgrades. Rolex added its own shock-resistant free-sprung balance, ultra-durable 28,800 VpH oscillation rate, and COSC-chronometer grade refinements to achieve unprecedented precision from the already outstanding El Primero. Aside from the Daytona movements (all), few El Primeros ever received chronometer certificates. Each year, this watch makes an appearance in the winner's circle at its namesake endurance race. As the official winner's gift for each class victor, the Rolex Daytona is the most coveted trophy in motorsports. Thanks to sponsorship of sports car racing's flagship North American event, Rolex and racing have been synonymous since 1964. This Rolex Cosmograph Daytona 16519 in 18-karat white gold is offered in outstanding condition. Due to the limitations of minuscule Zenith's factory capacity, far, far fewer of these five-digit Daytonas were built than the six-digit Rolex-powered successor. This rare white gold "El Primero" Rolex Daytona is ready for new roads and a new wrist... will it be yours? Video and content by Tim Mosso.