The attomol^® Caleidoscan 300 (CS300) is the further developed version of the attomol^® Caleidoscan 100 (CS100). Like CS100, it is a automated fluorescence imager with three measuring channels, which is used for imaging fluorescent microobjects, such as fluorescence and size-coded microparticles (beads) in attomol^® bead assays. The CS300 is driven by the attomol^® Caleidopro control and analysis software. Compared to flow cytometric measurement methods, the CS100 and CS300 are significantly faster. The evaluation of 32-wells by CS300 only takes approx. 5 minutes. The measuring system is characterized by a large linear measuring range and high precision.