Using this axis digital angle protractor, you can measure the angle between two faces, not only in earth gravitydirection. Press Angle key at the first face, and then rotate slowly and must keep the rotation axis to another testingface, 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, durable. 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 Plug Type: US / EU / UK (Optional) 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 Item Weight: Approx 119.7g / 4.2oz Package Size: Approx 17 * 13 * 4.5cm / 6.7 * 5.1 * 1.8in Package Weight: Approx 250g / 8.8oz Package List: 1 * Digital Angle Protractor 1 * AC Adapter 1 * User Manual