The A Michel 320 watch movement is an open face calibre pocket watch movement that was manufactured with options like a bimetallic screw balance and a Breguet hairspring. It was made in different sizes with varying heights, ranging from 4.2mm to 5.9mm. There are several bridge layouts and two base plates with different dial-feet positions and setting-lever springs. The movements are categorized into groups FHF 1 to 14, with designations starting from FHF 22. The A Michel 320 movement incorporates the following functions: stem wind and set, a sub-second hand, and it was commonly used around 1940.