Oxygen Regulator Type A-9A S2 Tracker given the rubberized interface tool

given the rubberized interface tool affixed to the spindle

The booklet contains maps of Japan and its major home islands

The pilot can select the mode of operation desired by use of the Reset/Stby switch located on the lower right corner of the instrument case

This "Rebecca" Receiver/Indicator is identified as ID-169A/APN-12 AT-2/APN2

so it could use repair

Oxygen Regulator Type A-9A S2 Tracker given the rubberized interface toolThis is a WWII era aircraft Oxygen Regulator Type A 9A as used across bomber and transport aircraft of the US Army Air Force and US Navy, such as the B 17 Flying Fortress (see image illustrating the location of the co pilot's regulator from the B 17F flight manual dated 1943). This example has a serial number prefix of AC41, evidence of a year of manufacture of 1941. The A 9A regulator was a low pressure continuous flow regulator (vs the on demand,