This was my grandfathers
Six-16 camera. It cost around US$16.
It used
Kodak 616 film with a negative size of 2.5quot;x4.25quot;. This was postcard size and useful before the invention of enlargers. Today it would be considered a medium format camera. You can't buy 616 film anymore but there are hacks to use 120 film. I found a
good story of someone who did that for a camera like this.
It worked the last time I tried it several decades ago.
Manually set speed, aperture (max f11) and focus. One mirrored view finder and one size range finder.
It utilized a Kodak BIMAT f/11 lens focal length unmarked (app.103mm). It's a 3 element triplet design with front element focusing produced for Kodak's entry level adjustable cameras.
I was able to find
a manual for it which makes for interesting reading.