On a lensatic compass, what is the function of the inner red ring?

The inner red ring on a lensatic compass is utilized to measure azimuths in degrees. When navigating or determining a specific direction, the compass needle aligns itself with the Earth's magnetic field, while the degree markings on the inner ring allow the user to read a specific angle from the north. This is essential for accurate navigation, as azimuths expressed in degrees provide a clear, universally understood method of indicating direction, enabling individuals to establish precise bearings and communicate their navigation goals effectively.

Using this feature effectively helps users determine their path or locations with confidence, as degrees are widely recognized in various geographical and navigational contexts.