Mix-n-Stain™ Small Ligand Labeling Kits are designed for rapid labeling of low molecular weight (MW 150 -5000) ligands without a purification step. Suitable ligands or substrates include SNAP-tag® , CLIP-tag™ and HaloTag® ligand derivatives that have an aliphatic amine. 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. It is suitable for labeling ligands for cell surface staining.