... and individual sound exposure meter standard of GB/T 15952.digital detection, automatic measuring range conversion, wide dynamic range,GB/T ... 3785,1-2010, IEC61672,GB/T 15952LCD digital displayfrequency range: 20Hz-12.5kHz Modal TL5618B Microphone Diameter 12 ... Lmax, Lae, E, Tm (time of measuring)4 digits LCD digital displayPower 2 pieces of batteriesPower consumption:25mA more than 24hours ...