QXL™ 570 dyes are optimized quenchers for rhodamines (such as TAMRA, sulforhodamine B, ROX) and Cy3 fluorophores. Their absorption spectra perfectly overlap with the fluorescence spectra of TAMRA, sulforhodamine B, ROX and Cy3. This characteristic makes QXL™ 570 dyes excellent quenchers for rhodamines (such as TAMRA, sulforhodamine B, ROX) and Cy3 fluorophores. QXL™ 570 C2 maleimide readily reacts with thiol-containing compounds.