PE-VF647 Maleimide is a bis-dye compound capable of thiol-reactive conjugation, using its maleimide group to form covalent bonds with thiol groups. The dyes contained in PE-VF647 Maleimide, PE, and VF, have excitation wavelengths (Ex) of 495 nm and 566 nm, respectively. The emission wavelength (Em) of PE-VF594 Maleimide is 665 nm.