The Eterna 1020S watch movement, produced between 1893-1895, was manufactured in 14,000 units. It featured a hunter calibre design, specifically the model 3. The movement incorporated a bimetallic screw balance and a ratchet positioned between plates. Additionally, it included a crown mechanism with a rocker bar, which effectively prevented unwanted hand movement during the switch from setting to winding. Notably, the Eterna 1020S supported the functions of stem wind and lever set, as well as a sub-second display.