The A. Schild 1138 watch movement was produced from 1937 to 1970, with a total production of over 3.5 million units. It featured various chrono mechanisms, and its parts were often interchangeable, leading to the occasional combination of parts from different calibers. The A. Schild 1138, 151, and modified parts were also compatible with minor differences. The movement included functions such as a manual-wind chronograph with a 60-second measurement capability, a subsecond display, and a switchable cam for 30/45-minute timing intervals.