This is practically a relic! Before there were e-book readers, i-Pads, tablets, in the Jurassic era of the '70s, we had this! Mine was blue. Actually, it was my brother's, because back then, my uncle preferred to give me a Malibu Barbie instead of this! But, since girls grow faster than boys (until they catch up and grow faster when they turn around sixteen), I would grab this from my brother. He is much much taller now, but I bet he will remember how I tried to get this from him and watch stills of Adam West in Batman!
And oh, this is called View-Master. Mine (my brother's, actually) was battery-operated (there was a tiny bulb like that of the flashlight's that would turn on), and if the double-A batteries wouldn't work anymore (even after I let them bake under the sun!), I would remove the back cover, go out (in the daylight of course. Nighttime and you wouldn't see anything!) and view stills.
Did you own a View Master way (waaaaaayyyy) back then?