Gyro Transmitter, AN5751-1, Flux Gate Compass System F8F This type of compass is

This type of compass is mounted horizontally

See photo from the TBM Avenger Pilot Manual dated Nov 1945

25 inches diameter and ~10 inches deep

see logo with the 3-crown symbol of Sweden on the inside flap

but does not engage the barometric pressure adjustment mechanism consistently

Gyro Transmitter, AN5751-1, Flux Gate Compass System F8F This type of compass isThe Gyro Transmitter AN5751 1 was an integral component of the WWII era Bendix Gyro Flux Gate Compass System used in aircraft such as the B 17, B 24, and B 29. The 7 component Flux Gate Compass system was designed to provide accurate navigational guidance using the earth's magnetic forces by minimizing interference from the systems of the aircraft, such as its turrets, guns, and engines. A flux gate gyro transmitter typically located within the wing