Based on Calibre 889, Calibre 899 incorporates many changes. A major difference is the winding system: The rotor rests on ceramic bearings like the contemporary "Autotractor" 975, and it is unidirectional like that movement, though 899 does not have all of it's other features. Adjustment is via four screws on the rim of the balance, since the hairspring is laser welded in place and there is no bridge like the Autotractor. The mainspring barrel was also enlarged and re-profiled gear train teeth reduce friction.
The 899 is made up of 219 components. It runs at 28,800 A/h, has 32 jewels, and a power reserve of 43 hours. Jaeger-LeCoultre currently uses this calibre in the Jaeger-LeCoultre Master Control and Jaeger-LeCoultre Master Compressor Diving Automatic Navy SEALs.