Valjoux 72

Legendary column-wheel chronograph movement produced from 1938 to 1974. Arguably the finest manual-wind chronograph ever made, the Cal. 72 features a 9-column wheel, dual-pusher design (implementing Willy Breitling's patent), 30-minute counter at 3 o'clock, 12-hour counter at 6 o'clock, and small seconds at 9 o'clock. Used in the iconic Rolex Daytona (as Cal. 722/727), Patek Philippe, Girard-Perregaux, Breitling, Universal Genève, and many other prestigious chronographs. Over 750,000 movements in the 23/72 family were produced. The movement's distinctive feature is the asymmetric pusher spacing - the 2 o'clock pusher is closer to the crown than the 4 o'clock pusher.