FluoroSpheres 6-Peak are polystyrene microparticles suited for daily monitoring of the flow cytometer. FluoroSpheres contain a mixture of 3.2 µm microparticles of six different fluorescence intensities. Each particle contains a mixture of fluorochromes to be excited at any wavelength from 364 to 650 nm. This broad excitation range allows the kit to be used in instruments with UV, and single or dual laser light sources.