Compass, Magnetic, Type B-20 Vertical Card, WWII, US Army Air Force Vulcan and by the USAF as

and by the USAF as the Low Altitude Bombing System

The housing had been repainted at one point

and comes in its original box

the small circular window between its 6 o'clock and center position changes from red (set-on)

Compass, Magnetic, Type B-20 Vertical Card, WWII, US Army Air Force Vulcan and by the USAF asHere is a WWII era Type B 20 Direct Reading Magnetic Compass, made by Autoflight, part number 2221. The B 20 Compass design is unique in that it contains a magnetic horizontal float suspended in damping fluid that engages the directional pointer on a vertical compass card to display direction. The pointer indicates the direction of aircraft flight. The knob in the lower left corner manually rotates the course indicating pointer (i. e., the two