The Bosch GAM 220 Professional Angle Measurer provides fast and precise calculation of angles. Angles can be transferred precisely onto workpieces by means of a mechanical locking screw. Specifications: Measurement Range: 0-220°. Measurement Accuracy: +- 0.1°. Vial Measurement Accuracy: +- 0.05°. Accuracy of Angle Calculation: +- 0.1°. Power Supply: 4 x AA 1.5 V LR6 Batteries (supplied) Arm Length: 40cm. Weight: 1.3kg.