TET NA NHS ESTER is an orange fluorescent dye used to produce a stable fluorescent signal in bioimaging. Optical properties of TET NA are similar to that of TET, CAL Fluor Gold 540. The excitation and emission maxima of TET NA are at 520/534 nm. NHS esters readily react with amino groups of biomolecules such as the ε-amino group of lysine or the amine termini of modified nucleotides to form stable amide bonds between dyes and biomolecules. We offer TET NA NHS ester for labeling biomolecules and amino-modified oligonucleotides in solid phase oligonucleotide synthesis.