The Felsa 313 is an open face calibre movement that serves as a simpler variant of the J38/1, specifically used for Jota models featuring steel pallets and a single jewel. The movement typically includes imitated balance screws and lacks a gilt base plate. Notable features of the J38A/1 movement include an indirect minute and hand friction clutch on the barrel, as well as a stem mechanism without a setting-lever spring between plates. Functionally, this movement offers stem winding and a sub-second display. It was primarily utilized around the 1940s.