This caliber JLC 899 was found in a Jaeger-LeCoultre Master Control Date in 18K gold (reference 176.2.40.S aka Q1542520). Each caliber 899 is said to be tested rigorously for 1,000 before leaving the factory.
Jaeger-LeCoultre
Jaeger-LeCoultre automatic movement caliber JLC 889/2. Adjusted to six positions and packed with 36 jewels. 42 hour power reserve. Found in a Master Control model originally purchased in 2001.