The ETA 2658 is a mechanical watch movement that was introduced in 1961. It features a ball-bearing rotor and a sophisticated excenter self-winding mechanism with just one gear stage. It incorporates a stem mechanism without a setting-lever spring and is equipped with Diafix combined settings for the escapement wheel. Notable functions of this movement include automatic winding, no manual winding, a sweep second hand, and shock protection. It has been utilized in timepieces starting from 1961 and beyond.