Sawyer's View-Master reels allowed you to view seven stereoscopic photographs per disc, usually of scenic places like national parks.  While most of the the viewers were personal models, others worked like slide projectors — load the reel up, turn off the lights, and the picture appeared on your handy screen or wall.

Unlike most projectors (and perhaps larger ones in the Sawyer catalog), the Junior Projector's image is pretty small — perhaps a couple of feet square at a distance of 10 feet. 

It is difficult to pinpoint the exact date of this unit. The patent goes back to 1940, consistent with the art deco styling and bakelite construction, but the earliest I recall seeing them in the ads and shops was ~1949. I got this one at a thrift shop, so its provenance is a mystery.