JMALL Folding Multifunctional Compass Mirror Meter Magnifier - 18 Compass  (White)

There are also two forms of the Orienteering Compass -- the Base Compass, and the Mirrored Compass. These are very similar except that the Mirrored compass allows for increased accuracy when actually shooting azimuths as you sight it like a rifle. Once you have an azimuth (target bearing) sighted in, you rotate the bezel (which houses the compass card with cardinal points) to exactly line up the orienting arrow on the card with the magnetic needle. Your azimuth bearing is now the number (in degrees) that lines up with your Sight Line (sometimes on base compasses referred to as Direction Of Travel line, or Index line).