The Duoplan led to the creation in 1929 of the world's still-smallest mechanical movement, the Calibre 101, whose 74 original parts (98 today) weighed a total of approximately one gram. The second family of watches equipped with the Calibre 101, Joaillerie 101 Étrier appeared in the 1930s. In 1953, Elizabeth II of the United Kingdom wore a Jaeger-LeCoultre Calibre 101 wristwatch for her coronation.