Advanced manufacturing techniques make the unit compact, great in appearance and convenient for use and maintenance. Effective anti-interference technology improves electrical stability and reduces fault rate. Two sample feeding modes: small cell and flow cell (automatic circulating & dispersing system (ACDS)); selectable for user with easy replacement. Mie scattering and Fraunhoffer diffraction theories are applied in data processing, both include R-R distribution and random distribution for selection. Interior computer controlled self-alignment system will focus lens automatically to improve accuracy; separate ACDS makes sample preparation more convenient. Specially designed light receiver array with 76 detectors improves resolution. User-friendly interface of test software makes for easy operation with options for saving results, locating details, comparing, merging, editing, deleting, and help. Six report forms in English; including cumulative particle size distribution of data and graph, frequency particle size distribution of data, histogram and typical particle diameter range such as D3, D10, D25,D50, D75, D84, D90, D97, D98, etc. Layout, color, and font of the report are editable.