ST-105 Class 1 Sound Octave Analyzer is designed to meet the latest international standards IEC 61620-1:2001 (or the equivalent ANSI S1.11 : 2004). ST-105 Sound Analyzer provides not only real-time analysis of sound in 1/1 and 1/3-octave bands for environmental noise measurements but can also perform sound intensity measurements and sound power measurements to be used for occupational noise measurements.