Stadimeter Mark III in Leather Case, US Navy C-47 which registers it on a

which registers it on a dial marked in revolutions per minute

California

Above that limit

and possibly others

This is an original (not reprint or CD) Handbook of Operation and Service Instructions for the Automatic Pilot Type C-1 System

Stadimeter Mark III in Leather Case, US Navy C-47 which registers it on aThis is an original WWII era Stadimeter Mark III as used aboard ships of the US Navy. A stadimeter is a rangefinder, used to determine the distance from the user to an observed known target. By viewing the target through the device and turning the knob until the presumed height of the known target is bracketed between the upper and lower limiters in the viewfinder, one can then read the distance of that target on the corresponding height on the side