The ETA 255.421 watch movement, also known as the Omega caliber 1310 Megaquartz 32 Khz, was introduced in 1973 as Omega's first in-house quartz movement. It boasts 8 jewels and operates at a frequency of 32,768Hz. This movement offers several functions, including a quartz controlled stepper motor, sweep seconds, quickset day and date, and a central sweep-seconds hand. It is an electronic quartz movement that provides accurate timekeeping and calendar features. The ETA 255.421 was produced from 1973 to about 1978.