Etekcity USB Digital Sound Level Meter 40dB-130dB with Battery Support A and C Frequency Levels For Musicians Passed the high standards of IEC651 TYPE 2 & ANSI S1.4 TYPE 2 for sound level meters AC Analog Signed Output for frequency analyzer level recorder or X-Y axis, FFT analyzer, graphic recorder, etc. to do statistical analysis of data logger Level Selecting Button Switches:40 ~ 70dB, 60 ~ 90dB, 80 ~ 110dB, 100 ~ 130dB, 40 ~ 130dB auto-power off and hold function Measures 40 to 130dB on large digital display