This is a Sachs-Huret Rival ARIS emblazoned with the word 'approved' and Galli's rooster symbol ('gallo' is the Italian for 'rooster'). Galli included this derailleur in some of its mid-range groupsets in the late 1980s.
The derailleur, itself, is a presentable, solidly constructed and reasonably effective unit. It has its cable clamp bolt mounted on a sprung arm - to give what Shimano called a 'light action'. In fact, compared to a Shimano Light Action derailleur of the time, the Sachs-Huret Rival ARIS was just slightly later to market, just slightly more expensive, just slightly heavier and indexed with just slightly less accuracy.
It's tough competing against a highly capable, 800 pound, gorilla like Shimano.