This vintage Zenith El Primero A3817 is one of the rarest and most collectible references from the legendary El Primero series. Produced in the early 1970s, this grail chronograph features a 37 mm stainless steel case with sharp lines and sporty proportions. The watch is powered by the iconic Zenith El Primero caliber 3019 PHC, one of the world’s first high-frequency automatic chronograph movements, operating at 36,000 vibrations per hour for exceptional precision. Its stunning original three-color dial combines contrasting blue, anthracite, and silver tones, creating outstanding depth and vintage character. The watch is completed by the correct Gay Frères “ladder” bracelet, an essential detail highly appreciated by collectors. A true milestone in vintage chronograph history and an iconic example of Zenith’s technical innovation.