Zetasizer series instruments are used for measurement of particles and molecules size from less than nanometers to a few microns, zeta potential and electrophoretic mobility, and molecular weight with dynamic light scattering, electrophoretic light scattering; and static light scattering, respectively. The Zetasizer system has multiple variants, including the new Zetasizer Pro and Ultra. These two new systems provide unprecedented ease of use and flexibility, as well as user guides and novel measurement techniques (such as MADLS® and particle concentration).