The A. Schild 1648 is an open face calibre pocket watch movement. It offers options of a bimetallic screw balance and a Breguet hairspring. This movement comes in various sizes, including 18.5 und 19''', with heights ranging from 4.2mm to 5.9mm. It features different bridge layouts, two base plates with varying dial-feet positions, and two slightly differing setting-lever springs. The assignment of these differences to specific groups and calibres is partially known. Comparing the related calibres provides insights into their similarities and variations. The A. Schild 1648 movement combines functions like stem wind and set, sub second, and was commonly used during the period around 1940.