Vintage 50s Magic 3 Dimensional Viewer Framed Kellogg's Advertisement

Vintage 40s or 50s Magic 3 Dimensional Viewer framed Kelloggs Corn Flakes advertisement. I believe this was on the back of a box and repurposed into the back of the frame, but the graphics are just so great! Eye hook on the horizontal end, see photos for details. Measures 6.75" x 4.75" x .5".