Applied Biosystems TaqMan QSY and QSY2 probes are dual-labeled probes used for real-time PCR with Cyanine 5 (Cy5) and Cyanine 5.5 (Cy5.5) reporter dyes. TaqMan QSY and QSY2 Probes are designed for optimal sensitivity and performance in multiplexed qPCR experiments for detection of up to 6 targets.