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