The ETA 766 watch movement, manufactured by Wostok Watch Factory Tschistopol, features indirectly driven minute and second hands which allow for a relatively large balance. The movement originally incorporated a Breguet hairspring and a fixed stud carrier, but has since been updated to include a flat hairspring and different mobile stud carriers. Functionally, the movement is manually wound and includes a sweep second hand, a date function that is set by changing 20:45-24h, and a hack feature. It was commonly used during the period around 1960.