Early Races have been generally timed by stopwatches mounted to auto dashboards, but as the complication was shrunk, they were much more generally witnessed on wrists, especially in the F1 and endurance racing heyday amongst the ’50s and ’70s. I'd personally Fortunately use Watches World again and would recommend them https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/