Sound db meter calibrated at factory, noise measurement range from 30 - 130dBA, accuracy: 1.5dB, resolution: 0.1dB. Disable the automatic off function, sound meter can continuously measure noise value Sound meter features backlight alarm, large LCD display, maximum/ minimum noise monitor, data hold function, auto/manual power off, disable the auto off function, sound level meter can continuously measure noise value, battery indication Decibel meter is ideal for neighbors noise complaints, job-site and noise pollution monitoring Portable sound level meter is light and compact design, easy to carry with you and operate with one-hand Noise meter comes with 3 pcs AAA batteries, a wind-proof sponge ball and user manual. The decibel meter has been adjusted properly, it can be used immediately after the battery being installed.