Wristwatch movement, 'The World's Smallest Movement' or 'The Smallest Watch in the World', Swiss lever escapement, left-hand wind, by Jaeger-LeCoultre SA, Geneva, Switzerland, 1929-1953, mounted on a stand (see note).
This Jaeger- LeCoultre '101' wristwatch movement introduced in 1929 remains the smallest mechanical wristwatch movement ever made. It was put into series production and remained available at least until the 1950s. It comprises 98 parts, measures 14mm x 4.8mm x 3.4mm, and weighs only 0.9 grammes (including the dial and hands). In 1903 Jacques David Le Coultre entered into a partnership with the chronometer-maker Edmond Jaeger and together they manufactured some of the most technologically advanced watches of the era.