Bosch GAM 220 MF Professional Angle Measurer for automatic calculation of single and double mitre angles without any other tools. A memory function allows for rapid calculation and transfer of angle, ideal for frequently used angle dimensions. Specifications: Measurement Range: 0-220 degree.Measurement Accuracy: ± 0.1 degree.Vial Measurement Accuracy:± 0.05 degree.Accuracy of Angle Calculation:± 0.1 degree.Power Supply: 4 x AA 1.5 V LR6 Batteries (supplied).Arm Length: 40cm.Weight: 1.3kg.