Toronto. From its earliest years the famous little Leica camera was offered with a companion projector. Various models were made to project black and white positives and especially film strips. When I was a school boy in the 1940s I operated a tiny SVC film strip projector to illustrate classes in grade school.
When Kodak came out with Kodachrome colour slides in the late 1930s, Leitz produced a home projector like the little SVC. The Leitz VIIIc was manufactured from 1938 through 1961 when it was replaced by various semi automatic projectors using slide trays rather than the manual slide changer or optional film strip mechanism. The VIIIc was variously designated as the Parvo (my version), Gnome II, and finally the Prado 100/150. My projector has a 100mm f/2.5 Hektor lens with a round black paper/cardboard lens box. I bought the Parvo, lens, manual slide changer and 5cm condenser set back in 1992 from Larry Boccioletti.
If you want an inexpensive branch of Leitz to collect, consider projectors – like flash guns, they are very inexpensive to amass. Unlike the cameras, lenses, and some accessories, the projectors have little background information readily available.