... SPECIFICATIONS Measuring Range: 40 dB ~130 dB(re.20 μPa) Sound Exposure: 0.1 ~ 199 ... , 10 min, 15 min, 20 min, 1 h, 4 h, 8 h, 24 h Standard: IEC 61672 - 1:2002 ... Pa Frequency Response: Free field Frequency Range: 20--8000Hz Reference Direction: Axial direction of microphone Polarized ... batteries Operating Voltage: 3V DC Battery Life: Approx. 20 hours Operating Current: 20mA ENVIRONMENT Temperature: 0°C ~ ...