The ETA 737 is a manual-wind chronograph movement with a 60-second timer and the ability to measure 30 or 45 minutes. It features a sub second hand and was produced in various series between the years 1937 and 1970. There were different chrono mechanisms available, and some series may contain interchangeable parts from different calibers, such as the Landeron 48, which has a larger pillar plate. Over 3.5 million units of this movement were manufactured during its production period.