RAF Bombsight Mk XIV Emergency Computor Ref 9/2648
This is an authentic original WWII-era Emergency Computor (sic) designed for use with the Mark XIV Bombsight in the British RAF's Avro Lancaster Bomber.
It appears to be a manual back-up device for use in an emergency, possibly if the mechanical computer within the bombsight malfunctioned. One side shows speed as measured in knots, while the computer on the other side shows speed as measure in MPH. This plastic or bakelite device has a circular slide rule that rotates to align rectified air speed with sighting angle.
Measures approximately 7 x 8 inches. The dials rotate stiffly.