The ETA 255.491 watch movement is an electronic quartz movement that features various functions. Its operation allows for the display of hours and minutes through mechanism A, while mechanism B enables the display of seconds. Additionally, mechanism C allows users to set the minute, starting from 0 seconds after release. The watch movement also includes a combined operation of A and C, which enables the setting of hours. The ETA 255.491 movement incorporates an LED quartz with a light emitting diode, and its period of usage is approximately from 1972 onwards. The movement utilizes a 12-hour time format and possesses an LCD display.