Graduated to give a direct reading to 10 seconds with a range of -2° to +110°. The quick accurate leveling of the 20 second per 2 mm level vial is accomplished by means of a clamp and slow motion tangent screw. This clinometers has been used in shipbuilding yards and is used to calibrate foundation points, machinery foundations, and other applications. Arc radius 6-7/8”. Base 5” x 12”. Complete with durable case.