Early Races were largely timed by stopwatches mounted to vehicle dashboards, but as the complication was shrunk, they have been far more normally found on wrists, specifically in the F1 and endurance racing heyday in between the ’50s and ’70s. Impressed by British pilot’s watches through the 1970s, Hamilton’s Khaki https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/