Low angle light scattering (LALLS) or laser diffraction is a measurement technique for particle size analyzers and particle count analyzers. LALLS offers a wide dynamic range and is the preferred standard in many industries that require stringent characterization and quality control. Often, low angle light scattering (LALLS) or laser diffraction is used to measure the output of a spray nozzle to determine the correct droplet size. Consequently, LALLS is used widely in pharmaceutical and agricultural applications. With LALLS, dry powders can be measured directly, and liquid suspensions and emulsions can be measured in a re-circulating cell. This provides high reproducibility and enables the use of dispersing agents and surfactants for the determination of primary particle size. Low angle light scattering (LALLS) or laser diffraction is nondestructive and unintrusive. Because the generated volume distributionis equal to the weight distribution where density is constant, LALLS is of direct relevance to chemical engineers. Other benefits include rapidity, with answers in under a minute; repeatability for reliable results; and high resolution. Although there is no need to calibrate against a standard, equipment performance can be verified easily.