5-HEX NA NHS ester is a pink fluorescent dye used to generate stable fluorescent signals in bioimaging. This dye can be used as a replacement for HEX, JOE, VIC, CAL and Fluor orange 560. NHS esters readily react with amino groups of proteins, such as the ε-amino group of lysine or the amine terminus of modified nucleotides, forming chemically stable amide bonds between dyes and biomolecules. We offer 5-HEX NA NHS ester for labeling biomolecules and amino-modified oligonucleotides in solid phase oligonucleotide synthesis.