The CLJ-BII (J) laser dust particle counter can simultaneously measure the number of dust particles in six particle size channels in one sampling, and can select to observe the number and changes of particles in one particle size channel, which can meet the needs of the pharmaceutical industry (pharmaceutical factories, drug testing institutes, hospital operating rooms, etc.); The electronics industry (semiconductor factories, production and processing of precision machinery, etc.); Food hygiene industry (precision processing of dairy products, sealed meat products, seasoning foods, agricultural products, etc.); Manufacturers of filters, inspecting the quality and efficiency of filters, etc; The inspection of clean rooms (areas) required for precision machining and precision testing in the fields of optics, aerospace, etc.