Seerite opaque projector

This is an opaque projector that projects still images from paper such as photos, art, drawings, or the postcard in the third picture; the projection is the fourth picture - no transparencies necessary. The second picture shows its interior, which is basically a set of light bulbs, mirrors, lenses, and a cooling fan (it runs hot if you use incandescent bulbs). You simply focus the image by sliding the lens tube in or out and change the image size by adjusting the projector’s distance from the wall or screen. Made in Newark, NJ by the Testrite Instrument Co. I estimate that it’s from the 1960s but I’m unsure of the year (the company dates back to 1919 and is still in business, now as Testrite Visual in Hackensack).