The Fontainemelon 72-2N is an open face calibre pocketwatch movement available in 18.5 and 19''' sizes, with heights ranging from 4.2 to 5.9mm. It offers options for a bimetallic screw balance and a Breguet hairspring. Variations include different bridge layouts, two base plates with varying dial-feet positions, and slightly differing setting-lever springs. Although the complete assignment of these differences to the FHF 1 to 14 groups and specific calibres like FHF 1144, 2144, 2146, 4144, and 4146 is only partially known, comparing the corresponding calibres provides a glimpse into their distinctions. This movement features stem winding and setting, sub-second functionality, and was commonly used around 1940.