Jaeger-LeCoultre 631

The Jaeger-LeCoultre caliber 631 is a quartz-based movement that drives a mechanical chronograph function. It contains 233 parts—a notably high count for a quartz caliber—and combines a 30-minute counter with a 12-hour counter. The movement was notably used by Jaeger-LeCoultre and IWC in their Pilot's Watch and Da Vinci chronographs.