5 7/8" x 8 1/4": double-sided, three panel fold-out
(6 panels). Switzerland: Paillard S.A. (1959).
Although it wasn't commercially available until 1960, the Bolex Sonorizer was advertised in this brochure from 1959. The M-8 Projector is pictured on the back, along with a short list of specifications.
