Wide measurement range: 30~130dBA, 35~130dBC Accuracy up to 1.5dB 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 100% Brand New With modern, compact, portable design. Easy to use Frequency weighting characteristic: A & C Time weighting characteristic: Fast & Slow AC/DC output Bar graph indication Equipped with sponge ball to filter-out unwanted signals. Max reading hold USB interface Analyse software Auto power off Overload indication: OVER/UNDER Auto backlight display Low battery indication Powered by 4x1.5V AA batteries (not included) Approved by CE/ROHS/FCC standard