Chronometric Tachometer / Disk Speed Indicator BS Mk15 for Testing Norden Sight F-100 B-50 Superfortress

B-50 Superfortress

The fluid is low by about a 1/2 teaspoon

and US Navy's PBY5A Catalina and PB4Y Privateer

So it is possible that there is some connection there

type AN-5825-7

Chronometric Tachometer / Disk Speed Indicator BS Mk15 for Testing Norden Sight F-100 B-50 SuperfortressHere is a WWII era Chronometric Tachometer Disk Speed Indicator Kit, made by Technical Oil Tool Co. (TOTCO), used by bombardiers and technicians to check the proper operation of the Norden Bombsight The kit contains the disk speed indicator, two tachometer tips, instructions, and a metal case with a rubber lined compartment. It is in very good condition given its age. The case measures ~4. 5 inches long, 3 inches wide, and ~1. 5 inches deep.