Our CF® dye hydrazides are bright, extremely water-soluble and nontoxic. These properties make the dyes excellent fixable polar tracers for microinjection into cells. Hydrazides also can be used for labeling aldehyde or ketone groups, however, for this application we recommend using the more reactive CF® dye aminooxy forms. 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®647 dye has excitation/emission at 650/665 nm.