It's a Kodak Duaflex IV, a twin lens reflex camera made by Kodak between 1947 and 1960.
I will use it for Through the Viewfinder (link to tutorial) pictures.
The photo above shows you one of my 'old' toys, seen through the viewfinder.
I didn't use a contraption but in my stream you can see some pictures taken
with the use of a contraption.
This is the real stuff not a fake like this one.
I will post it in these groups for sure:
"Noise & Dust / TTV"-group and
"Pure TTV (the old fashioned way)"-group.