The Hanhart 55 is a manual-wind chronograph movement used in watches produced between 1937 and 1970. Over 3.5 million units were made during this period, with various chronograph mechanisms available. The movement featured interchangeable parts, allowing for the occasional use of components from different calibers. It included functions such as a sub-second indicator, a 60-second and 30/45-minute chronograph, a tag at 10:30h for time setting, a pusher at 4:30h for date adjustment, and a pusher at 1:30h for month adjustment. It also featured a calendar display.