WWII Driftmeters (Type B-3, Gyroscopic) Used on Bomber Aircraft

This a pair of rare Drift Meters used by the United States on bombing raids. Nicely mounted on heavy plaques for display. They were amazingly hi-tech devices for their time, are great conversation pieces, and worthy of being in a museum. Manufactured by the Pioneer Instrument Division of Bendix Aviation, and were used on bombing aircraft during WWII by the navigator to measure wind conditions in order to navigate the aircraft (especially at high altitudes). From my research, I have found out that they were at least used on the following aircraft:
C-47,
Boeing B17D "Swoose",
Douglas C-124,
Modified Halifax bombers (Royal Air Force 518 Meteorlogical Squadron)
and the B-25B (Mitchell).
Notably, a squadron of sixteen B-25B's were used in the DooLittle Raid on Japan on April 18th, 1942 (four months after Pearl Harbor).

Both units have the metal plates with the Model and Serial Number. One of the units also has a metal plate with "Instructions for Use", all still quite legible. Overall these are in great condition. They came from the estate of an avid WWII aircraft memoribilia collector, and displayed indoors.