The Girard Perregaux 26.3 watch movement was produced between 1937 and 1970, with over 3.5 million units manufactured during this time. It featured various chronograph mechanisms, with interchangeable parts leading to occasional series being produced with components from different calibers. The movement included functions such as a manual-wind chronograph with a 60-second and 30/45-minute timing capability, a sub-second hand, a date display at the 6 o'clock position adjustable by +/- 24 hours, as well as a chronograph and calendar feature.