One of the more widely used 16mm non-sync cameras, it is made in Switzerland by the Paillard Company. There are many varieties, non-reflex, reflex, springwound and electric motor driven. But when someone says “Bolex,” typically they mean a reflex, springwound model, such as the Rex-4.
Glossary of Film Terms - http://homepage.newschool.edu/~schlemoj/film_courses/glossary_of_film_terms/
reprinted with permission