Quenchers with no native fluorescence that have replaced TAMRA (which fluoresces) as a quencher. They are also called non-fluorescent quenchers (NFQ). The prototype was DABCYL which has been eclipsed by black hole quencher (BHQ) dyes. BHQ dyes offer greater spectral overlap with reporter dye emission profiles than DABCYL (the original quencher TAMRA is not a dark quencher). In fact, the BHQ dyes have the best spectral overlap over the entire range of currently used reporter dyes. Dark quenchers allow flexibility in the design of multiplex assays by enabling the choice of spectrally well-resolved fluorophores with little or no spectral crosstalk (overlap). BHQ dyes can be used in any chemistry that requires a quencher (TaqMan, beacons, scorpions etc). See the Black Hole Quencher Dyes page and Brochure (Biosearch Technologies).