The A. Schild 1654 watch movement, produced from 1975 to 1983 with a total of 342,123 units, is often utilized as a base for modules with additional functions. Its low-profile design incorporates a free section opposite to the stem, allowing the automatic module gear to extend into it and maintaining a low overall height. The movement features an automatic and sweep seconds functionality, with an optional absence of a second hand. It also includes a quickset date feature and a hack feature.