PHYSIALB Clinometer Handle Compass is a reproduction of an antique Clinometer compass. The Handle Compass gets its name from its "handle" shaped sight, which actually serves two purposes: With the compass level, an object can be viewed through the peep sights to determine its magnetic heading. The second and most interesting purpose is when tilting the compass on its side and viewing an object through the sights, its angle of elevation or declination can be found. A weighted pendulous arm beneath the compass needle can be read from one of three scales: Angle in degrees beneath the zenith (from straight up), angle in degrees of elevation or declination, and in inches per yard of slope. The clinometer compass has a needle lift mechanism to protect the compass jewel and the pendulous arm when being transported.