Application: it is used to calibrate the sound level meters. Model: SL5866 Standard: GB/T3785, IEC651 Type2, ANSIS1.4Type2 Function: SL Measuring: A .40-125dB Filter Detection characteristics: fast/slow Resolution:0.1dB Accuracy: 1dB Display: LCD display Power supply:1x9V 6F22 battery Battery indicator: low battery indicator Dimensions: 195x72x31mm Weight (not including probe): 195g