1944 M2 Compass

[72 usmc]

Military Lensatic Sighting Compass in mils. I still have mine when in m48s.
Conversion factors:
https://www.compassdude.com/compass-units.php

Quote

Mils:
Another unit of measure, the radian, is used mainly by militaries in artillery, tank, and mortar gunnery.
There are 2 PI radians in a circle. PI is a constant of approximately 3.1416. That is 2 * 3.1416, or 6.283 radians. Divide each radian into 1000 mil-radians and you see there are 6283 mil-radians in a circle. Mil-radians are called mils for short.
17.78 mils equal 1 degree. end of Quote

Just like an geological or archaeological Brunton compass, but not 360 degrees. Our military maps were in mils. A new Brunton runs $400 +. You got a deal of the year!