The ETA 2790-1 watch movement, introduced between 1966 and 1970, boasted being the thinnest automatic movement during that time. Its notable features included a micro-rotor mechanism with four ball-bearings, Girocap combined settings for the escapement wheel, and an indirectly driven minute hand which allowed for a low profile design. Although differences between the 231 and 2301 models are not fully known, the ETA 2790-1 movement showcased automatic functionality and was in use from 1966 to 1970.