101

The Jaeger-LeCoultre Calibre 101 is a hand-wound mechanical movement celebrated as the world's smallest mechanical caliber. Debuting in 1929 and remaining in production, it measures 14.0 by 4.8 mm with a 3.4 mm thickness, housing 98 parts and 19 jewels. Its diminutive size enables integration into fine jewelry pieces, operating at 21,600 vibrations per hour (3 Hz) with a 33-hour power reserve, all crafted in-house by Jaeger-LeCoultre.