The ETA 772 is an open face calibre mechanical watch movement with a unique crown mechanism featuring a rocker bar and a ratchet on the back side. It includes a crown wheel that does not serve a specific function and imitates balance screws with remarkable accuracy. The left-handed ratchet-wheel screw and varying bridge shapes distinguish the 220 from the 283. This movement offers functions such as stem winding and setting, along with sub second display. It was predominantly used around 1925.