Aminooxy dyes have an aminooxy reactive group, which can be used to label a target molecule with an aldehyde or ketone group. An aminooxy group readily reacts with an aldehyde or ketone group to form a stable linkage without the use of a reducing agent. 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 fluorescent CF®633 dye has excitation/emission at 630/650 nm.