feature:High precision 0.05, high resolution 0.01. Lithium-ion battery is rechargeable and durable. High resolution, professional measurement. Single and double axis, convenient angle measurement. Dual axis and single axis with user friendly LCD display angle. V-shaped housing for easy installation in corners or pipes. With a 7-sided magnetic base, you can set audible alarms within the angle range, any angle measurement. The unit can be charged by connecting a USB cable to the unit and the USB port of the computer.With this axis digital protractor, you can measure the angle between two faces, not just the direction of Earth& 39;s gravity. Press the angle key on the first face, then rotate slowly, you have to keep the rotation axis pointing to the other test face, once you don& 39;t move the unit, it will show the angle. Any angle measurement uses gyroscopic technology.