The Valjoux Regulator
The so-called Valjoux two-piece index regulator was created in the 1970s and was first used in the Valjoux 7750 family. It has a distinctive "c-clamp" or lyre shape with a dagger-shaped index. Later examples use the rotating block found on the ETACHRON system to maintain uniform contact with the hairspring.
The Valjoux regulator was originally used on the ETA Valgranges line, but it was later dropped, leaving just the eccentric screw type ETACHRON system. Most later 7750 family movements similarly dropped the Valjoux index as well, with some OEM movements still using it and others using a simpler ETACHRON corrector.