The Unitas 329 watch movement is an open face calibre with a bimetallic screw balance featuring four adjustment screws. It utilizes a Breguet hairspring and a cam disc regulator. It is equipped with a negative stem mechanism specifically designed for the US market. In later samples, a click and regulator, as exhibited in the Zenith 16''' model, were added. The movement functions include stem winding and setting, as well as a sub-second display. This movement was commonly utilized around 1908.