The NANO-flex® II 180° DLS system measures particle size distributions of suspensions and emulsions in the range of 0.3 nm to 10 μm and concentrations up to 40 % by volume. The principle of heterodyne 180° backscattering applied here is characterized by its high selectivity in the nm range and a very high resolution; it is also suitable for samples with a wide or multi-modal size distribution. Due to the low penetration depth of the laser light, samples of high concentration are measured without disturbing multiple scattering. Compared to cuvette based systems, many samples can be measured without dilution in original concentration. The dip-in probe used in the NANO-flex® II has a diameter of 5.5 mm and allows a wide range of applications. In conjunction with the IPAS extension, particle size distributions can be measured inline. In combination with the Stabino® II, stability ranges and critical coagulation points can be determined.