Digital Angle Finder Protractor 0.01° Resolution Angle Gauge Dual Axis Level with Backlight Woodworking Measuring Tool Using this axis digital angle protractor, you can measure the angle between two faces, not only in earth direction. Press Angle key at the first face, and then rotate slowly and must keep the rotation axis to another testing face, It will then show the angle once you not move the unit. Any angle measurement is using gyro technique.  Features: High accuracy ±0.05°, high resolution 0.01°. Li lon battery rechargeable, convenient e. High resolution, professional measurement. Single and dual axis, convenient to measure the angle. Dual and single axis with user friendly LCD display angle. V shape case for easy to fit at the corner or pipe. With 5 Side Magnetic base, audible alarming at settable angle range, any angle measurement. The unit could be charged by connecting the USB cable to the unit and a computer's USB port. Specifications: Color: Red Accuracy: 0 to 20°: ± (0.05°)  20 to 70°: ± (0.1°)  70 to 90°: ± (0.05°)  Measuring Range Single Axis: 360° , Dual Axis: ±40°  Resolution: 0.01°  Response time: <0.4 second Zero offset drift angle per °C: 0.0058°(typical)  Operating temperature: 0 to 50°C (32 to 122℉) Storage temperature: -10 to 60°C (14 to 140℉) User Interface: Mono color LCD with backlight  Supply Power: Rechargeable Li Polymer 3.7V  Charger port: 5V 500mA Mini type-B USB port  Power Consumption: tandby: 10uA, Operation: 20mA  Standby Battery Life: 4000 hours  Operating Battery Life: 40 hours  Magnetic Base: set on 4 corners  Magnetic Force: N48  Item Size: Approx 7 * 7 * 2.8cm / 2.7 * 2.7 * 1.1in