Overview: This unit was designed according to following standards: A. International electrician committee standard: IEC PUB 651 TYPE2 B. US national standard: ANSI S1.4 TYPE2 Measuring range: 30~130 d BA;35~130 d BC Accuracy: ±1.5 d B Digit amp; Resolution: 5digits amp; 0.1 d B Frequency response: 31.5 Hz ~8.5 K Hz Measuring level: 30~130, 40~90, 50~100, 60~110, 80~130 Frequency weighting characteristic: A amp; C Time weighting: FAST/SLOW Sampling rate: 2times/second Microphone: 1/2 inch polarization capacitance microphone AC/DC output Max reading Barcode indicate the value Overload indication: OVER / UNDER Low battery indication Power: 9V battery 1pcs or DC 6V 100m A adapter Specification: Weight Approx:180g Size Approx:22 x 7 x 3