The ETA 847 watch movement is an open face calibre movement that features a Breguet hairspring. It is optionally equipped with Reed's regulator. The differences between the ETA 847, 162, and 165 are not known. The movement registers list only the open-face variant of the Felsa 161, while Ronda additionally includes the ETA 847, 162, and 165. The ETA 847 movement includes functions such as stem wind and set, sub second, and was commonly used around the year 1932.