Digital protractor uses angle sensor technology to calculate exact angles simply by tilting it to the desired angle. Reading is always displayed in an upright position at any angle. The V-Groove ensures it sits flat against any metal surface (such as miter, table saws, etc.), round objects, curved surfaces or cylinders such as pipes, shafts or rods while the 2 powerful magnets on the bottom plate for secure the attachment. With care, you can also use it on aluminum or wood. Features: V-groove base plate with strong built-in magnets Full range 360° measurement Angle Finder, Protractor and Level Hold Data feature Simple self-calibration Upright enabling viewing at all angles High-impact, high-precision machined aluminum framework Zero references can be set at any angle Absolute and relative measurement conversion Specifications: Measuring Range: 4 x 90° (0~360°) Resolution: 0.1° Accuracy: 0° and 90° (= 0.1° based on horizontal position, relative to the ground level position), rest of angle = 0.2° Operating Temperature: 0~50°C (0~122°F) Operating Humidity: 0~85% R.H. Working Current: < 100 µA Power: 1 x 3V CR2032 Battery (included) Battery Life: 2000 hours in continuous use Dimensions: approx. 151 x 60 x 32mm Weight: approx. 292g (including battery) Set Includes: 1 x Digital Protractor 1 x 3V CR2032 Battery 1 x Soft Protective Pouch English Quick Start Guide Standard Factory Package