This decibel meter is applicable for the measurement of noise engineering, quality control, health prevention, treatment and various environmental noises.
But it is account for the relative loudness perceived by the human ear.The value will fluctuate according to the different distance sound source.

Specifications:

Sound pressure accuracy: ±1.5 dB (sound pressure standard, 94 dB @ 1KHz).
Sound pressure accuracy: ±5 dB (sound pressure standard, 94 dB @ 8KHz).
Sound pressure frequency response: 30Hz - 8KHz.
Dynamic range of sound pressure: 50 dB (for each measurement gear level).
Sound pressure measurement scope: 30-130 dBA, 35-130 dBC.
Sound pressure frequency weighting characteristics: A and C characteristics.
Dynamic characteristic of sound pressure: FAST 125ms, SLOW 1sec
Microphone: polarized capacitive microphone.
Digital display: 4-digit, resolution: 0.1 dB, sampling rate: 2 times/sec.
Analog bar display: Each analog bar represents 1 dB, sampling rate is 20 times/sec.
Measurement gear level: 30-80 dB, 40-90 dB, 50-100 dB, 60-110 dB, 70-120 dB, 80-130 dB, 6 gear levels in total.
Below or above limit prompt: indicated with “UNDER”± or “OVER” display.
Power supply:4 AAA batteries 1.5V

Package list:

1 * Sound Level Meter(Batteries not include)
1 * User Manual

Note:

1.Do not use the meter in hot,humid environment.
2.If the meter is not to be used for a long time, remove the batteries to avoid electrolyte leakage damaging instrument.
3.If you want to calibrate it , it needs Primary standard acoustic source, acoustic environment,Normally only the third testing organization or the credited laboratory could do it.