The Tajima Slant AL200 is a rotary angle meter which is designed to provide an easy way to measure the angles of slopes and inclines with one hand. It is equipped with a durable, lightweight aluminium frame and a magnet for affixing to metallic surfaces. To Measure an Angle or Pitch: 1. Place the bottom of the pitch / angle meter flush with the surface to be measured. 2. Rotate the thumb-screw knob until the bubble in the vial is centered between the alignment lines then read the angle or pitch calibration mark at the index pointer. 3. Invert the pitch / angle meter to measure a downward slope. To Set an Angle or Pitch: 1. Rotate the thumb screw knob until the index pointer is positioned at the desired angle or pitch calibration mark. 2. Place the bottom of the pitch / angle meter flush with the surface to be set. 3. Rotate together until the bubble in the vial is centered between the alignment lines. SpecificationsMeasurement Range: 0° - 130°Accuracy: +/- 1°Dimensions: 250mm