VLIKE Digital Sound Level Meter complies with IEC651 type 2 and ANSI S1.4 type 2. It also could be called as DB reader, phonometer or SPL meter,accumulate sound level value data for noise dosimeter, can be used as a noise monitor testing sound intensity to reduce Noise pollution, avoiding the risk to hearing damage. But it is account for the relative loudness perceived by the human ear.The value will fluctuate according to the different distance sound source. Whether you're monitoring workplace machinery, installing audio or alarm systems, or handling product noise certification and reduction, VLIKE Digital Sound Level Meter gets the job done. There are two weighting modes for the mini Decibel Meter, A and C frequency-weighting mode, there is a A/C key press for selection. A is for measuring the sound level within the human audible range, the test range is 30-130 dBA, it?s used for the protection of workers against noise-induced hearing loss. And C is for measuring the actual sound level, which can be sensitive to the higher frequencies human couldn?t hear, the C weighting is most meaningful for describing the frequency response of real world sounds. And it?s test range is 35-130 dBC. But we are more sensitive to the lower frequencies, so if we use C weighting, the sound level will be higher than acoustic sound. The sound level meter is an instrument used to realtime measure the sound level,such as sound level around factories,workshops,schools,residential,offices,road,audio etc Battery not include, Can not keep and generate a report directly from the device It also can be appropriate for noise engineering,product quality control,health prevention and treatment,etc.This audio noise measure device is a great tool for checking, monitoring or controlling and test the sound level of any environments. It is widely applicable for personal, families, business, studies, industrial and etc With the measuring scope from 30 to 130dB and shifting function. Digital display,good antiinterference performance,power saving With the backlight feature,it is appropriate for gathering the sound data at night.Backlight auto power off function is provided.With power saving and highreliability circuit design,welldesign highefficiency power supply circuit makes the batteries more durable Composite material injection molding process is adopted for casing with antidrop structure design.It is not only extremely wearresisting,but also elegant,Its a mini handheld portable sound level reader