The Eterna 852S watch movement, similar to the ETA 717 movement but with lower specifications, is equipped with an early Incabloc shock device. The differences between the Eterna 852S and the Zentra 295 movements are unclear. There are various samples of the Eterna 852S movement that exhibit both bridge layouts shown in the archived records. The Eterna 852S movement is a manual wind movement with sub-second functionality, and it was primarily used around the year 1935.