High resolution, professional measurement. Li- battery rechargeable, . Using this digital angle protractor, you can measure the angle between two , not only in earth direction. Press Angle key at the first face, and then rotate slowly and must keep the rotation to another testing face, It then show the angle once you not move the unit. Any angle measurement is using gyro technique. High accuracy ±0.05°, high resolution 0.01°. Single and dual , convenient to measure the angle., Weight: 1.14419913978 pounds, Manufacturer: Kueohse