Using this axis digital angle protractor, you can measure the angle between two faces, not only in earth gravity 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. 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: lt;0.4 second Zero offset drift angle per C: 0.0058(typical) Operating temperature: 0 to 50C (32 to 122) Storage temperature: -10 to 60C (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: Approx119.7g / 4.2oz Package Size: Approx17 * 13 * 4.5cm / 6.7 * 5.1 * 1.8in Package Weight: Approx250g / 8.8oz Package List: 1 * Digital Angle Protractor 1 * AC Adapter 1 * User Manual