"F" is for Falcon
Falcon was a name given to many inexpensive, often plastic cameras, mostly manufactured by Utility Manufacturing Company.
The company was founded around 1934 and was sold to the Spartus Corporation of Chicago sometime in the 1940s.
The Falcon Miniature - c1938

Two
Falcon Minicam Junior
s with different body styles - c1938

The
Falcon Model 4
- 1939-1942

Falcon Junior
- late 1930s

The back of the
Falcon Model F
showing the movable cover for the red windows - c1938

The Falcon Special
, and upgrade from the Falcon Model F - c1939. On top is an extinction meter (a simple light meter) next to the viewfinder. The back of the Falcon Special is similar to that of the Falcon Model F.