HMK-CD4 Nano Particle size analyzer is designed and produced according to international standards ISO13320 and ISO13321. It works by dynamic light scattering photon correlation spectroscopy principle. The particle size distribution is calculated by sensing fluctuation of diffracted light by the particles when particles in different size do Brownian motion in the liquid at different speeds. The testing is automatically completed in analysis software in a computer. The unit automatically selects the best test parameters such as channel number and delay time etc. HMK-CD4 Nano Particle Size Analyser features stable and reliable work, easy operation and fast measuring speed. It takes only 2 to 5 minutes to measure a sample. Multiple automatic continuous testing optimizes the test accuracy and repeatability. The test results are automatically saved by a computer. It is use-friendly when view or print the analysis report. HMK-CD4 has become a preferred instrument in applications of nano powder production and research.