Dhuli Digital Sound Level Meter Noise Meter Decibel Tester GM1351 Sound Meter

Compact, Lightweight Design, Easy to Use. There is a calibration knob. You can make use of the calibration function to ensure the accuracy of measuring noise value, reducing error. With a wind-resistant ball, while reducing the effects of wind noise. It is Designed to fit comfortably in the palm of your hand. Auto power-off or manual shutoff by pressing the power button for two seconds. MAX/MIN Hold Function will hold the highest/lowest reading until a higher/lower reading is picked up. Normally you don’t need to calibrate it because it was calibrated before delivery. There is a a calibration knob. You can find some tool fit the knob size to poke into the knob. Like needle, small cross screwdriver, iron nail.