Reviewed by Dustin - 21st Oct, 2018 Milli, radians. It does not matter if your compass is calibrated in degrees, Mils, bananas or anything else. The military use mils coz it can be easily used to estimate distance. An object 25 mils wide at 1000 metres = 25metres A line of 5 parked battle tanks 55 metres wide showing 50mils on a sighting compass =1,100 metres distance. A useful tool in ww1, ww2 and today. Providing you yourself are not a tool.