Jaeger-LeCoultre 839

Caliber 839 is a manual-winding ultra-thin movement manufactured by Jaeger-LeCoultre. Introduced in 1955, it measures just 1.85mm thick, making it one of the thinnest movements ever produced. The caliber was the basis for Vacheron Constantin's reference 1003 movement. Part of Jaeger-LeCoultre's in-house 8xx family, the 839 remains a landmark in historic ultra-thin watchmaking and is now discontinued.