Accelerometer, G-Meter, AN-5745, Type B-3 WWII B-17, B-24, B-25
Here is a fine example of a WWII-era Accelerometer, made by Kollsman, part number 691K-02. This type of accelerometer appeared in versions of the Boeing B-17 F &G models, Consolidated B-24 E, and North American B-25D bombers of the US Army Air Force during WWII, according to the Maintenance Interchangeability Chart dated Feb 1945.
The accelerometer has 3 pointers: a main pointer that instantaneously rotates counterclockwise when the aircraft experiences negative G's, and clockwise in the instance of positive G's. The two auxiliary pointers located behind the main pointer rotate to indicate the maximum negative or positive G's experienced by the aircraft until reset by turning the knob clockwise.