Near-IR CF® dye free acids are control dyes for studies that involve CF® dye succinimidyl ester conjugated to antibody, protein or peptides. CF® dyes are Biotium's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. Near-infrared fluorescent CF®770 dye has excitation/emission at 770/797 nm.