This leaflet describes the how to fit and adjust the DNB 66 derailleur. There are also some rather pleasant exploded diagrams for those of us who love those kind of things.
I am unsure of its date. On the one hand, its crisp presentation makes me think it is from the 1970s. On the other hand, 3 speed derailleur systems using 1/8" chain were passé even by 1969.
The leaflet also shows that:
Browse associated derailleurs.
DNB 66 red 1965?