1951 Argus Argoflex Forty 620 film
Built May 1951, this is a Argus Twin Lens Reflex camera.
The viewfinder (upper lens) is fixed focus but you can (and must) "best guess" the focus on a rotary knob for the exposure (lower) lens.

The "40" includes focus and shutter speed control its cousin the 75 lacks (errrrr - I own one of those too..... don't tell my wife....)