Gun Camera, 16mm, Gun Sight Aiming Point, Type M-4A US Navy USSR and the right engine is

and the right engine is on the lower scale

and widely used on aircraft in the 1930s through 1950s

This is a fine example of an WWII-era Suction Gage

The E-4 System was used in the late 1940-1950's and was still in use in some 1960's aircraft

Weston model 301

Gun Camera, 16mm, Gun Sight Aiming Point, Type M-4A US Navy USSR and the right engine isGun Sight Aiming Point (GSAP) Cameras are electrically operated motion picture cameras which were used across US Army Air Force and US Navy fighter and attack aircraft during WWII and the Korean War. These cameras were designed to record results obtained in aerial and ground gunnery training and for producing visual records of aerial combat. By the end of WWII, the AN N6 GSAP cameras were the standard for this application. This example, the M 4 camera