The El Primero caliber 400 is an anachronism, but a wonderful one. The first high-frequency automatic chronograph movement, it was introduced (along with the Seiko 6309 and the Breitling/Heuer/Buren caliber 01) in 1969 and it has, rather astonishingly, persisted down to the present day. The movement’s design, however, is also a relic of its time – for instance, there are a number of different size screws, more than you’d see in a movement designed today, which makes manufacturing comparatively time, labor, and cost-intensive. The Chronomaster Sport, launched today by Zenith, uses a new movement: the caliber 3600, which is designed to reduce parts count, take advantage of modern materials and manufacturing processes, and offer improved functionality.