The Girard Perregaux 23 watch movement, produced from 1941 to 1945 with fewer than 20,000 units, features a bimetallic screw balance and a Breguet hairspring. Serial numbers for this movement begin with 200,000, and later samples may be nickel- or silver-plated. It functions as a manual-wind chronograph with two sub-dials indicating 60 seconds and 30 minutes, respectively, and utilizes a pillar wheel mechanism. Additionally, it includes a sub-second function.