This sound meter has been designed to check compliance with safety regulations and perform acoustic analysis by safety engineers, health, industrial and safety offices as well as quality control. Uses 2 different weighting filters required by the IEC651 and ANSI S1.4 Type 2 for audio filtering. The A weighting 30~130dB is good for general low to moderate ambient noise sound level and the C weighting 35~130dB for measuring sound level of acoustic material control in various environments eg. loud low-frequency background noise.