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. Far-red/near-IR fluorescent CF®680 dye has excitation/emission at 681/698 nm.