This 180° Clinometer can be instantly adjusted through 3° to a base, and then angles can be measured directly in relation to this base and read to 5 minutes. Divided to single degrees 90-0-90 degrees. Vernier arm may be moved through the full graduation range and locked at any point. The 120 second per 2 mm spirit level is centered easily and quickly by turning the knurled. Measures: 7.25” x 2”. Height is 5”.