The Illinois 404 watch movement is an open face calibre option with a choice of a bimetallic screw balance or a Breguet hairspring. These pocketwatch calibres are available in sizes 18.5 and 19 inches, with heights of 4.2, 5.0, and 5.9mm. There are different bridge layouts, two base plates with varying dial-feet positions, and two slightly differing setting-lever springs. While the specific assignment of these differences to FHF groups and calibres is not fully understood, comparing the corresponding calibres provides some insight. The Illinois 404 movement offers features such as stem wind and set, subsecond, and right setting. It was commonly used during the approximate period of 1940.