The JLC 864 is a watch movement from Jaeger-LeCoultre.
The 864 (and derived JLC 864A is an hand-winding movement made up of 142 pieces. It runs at 21600 vph, has 19 jewels, and a power reserve of 48 hours.
Like the related JLC 854, the JLC 864A is a GMT calibre that can display a second timezone on the rear face. It features a small inset corrector button rather than the large button used on the newer JLC 854/1.
Jaeger-LeCoultre currently uses this calibre in just one watch