VersaComp Antibody Capture Bead kit provides both positive and negative microspheres that can be used to set compensation for multicolor flow cytometry experiments. The positive population captures conjugates in single color stains and recognizes all mouse and rat isotypes, most hamster isotypes and rabbit polyclonal IgG. The negative population provides fluorescence similar to unstained cells across the different excitation/emission wavelength combinations. This combination can be used to set up compensation to correct for spectral overlap.