AAT Bioquest's iFluor® dyes are optimized for labeling proteins, in particular, antibodies. These dyes are optimized to have minimal fluorescence quenching effect on proteins and nucleic acids. Our iFluor® 680 dyes have fluorescence excitation and emission maxima close to 680 nm and 700 nm respectively with good photostability. These spectral characteristics make them an excellent alternative to Cy5.5®, IRDye® 700 and Alexa Fluor® 680 (Cy5.5®, IRDye® and Alexa Fluor® are the trademarks of GE Healthcare, Li-COR and Invitrogen respectively). ReadiLink™ labeling kits essentially only require 2 simple mixing steps without a column purification needed. iFluor® 680 SE used in this ReadiLink™ kit is reasonably stable and shows good reactivity and selectivity with protein amino groups. The kit has all the essential components for labeling ~2x50 ug antibody. Each of the two vials of iFluor® 680 dye provided in the kit is optimized for labeling ~50 µg antibody. iFluor® 680 SE protein labeling kit provides a convenient method to label monoclonal, polyclonal antibodies or other proteins (>10 kDa) with the iFluor® 680 SE.