BioVision's PE-Cy5 is a tandem FRET conjugate dye, combining R-PE (240 kDa) and a cyanine dye (Cy5). The PE can be excited at 488 nm and functions as an efficient energy donor for the Cy5 which acts as an energy acceptor. Fluorescence emission maximum of the conjugate is around 670 nm. PE-Cy5 can be used with any flow cytometers equipped with a 488 nm laser and can be detected in FL3 channel.