Atto Oxa12 is a red-emitting label and a lipophilic variety of Atto 655. Characteristic features of the label are strong absorption, good fluorescence quantum yield, very little triplet formation, excellent thermal and photo-stability, and outstanding ozone resistance.Atto Oxa12 is a cationic dye (charge ⁺¹). Absorption and fluorescence are pH independent in the range pH 2 to 11, used in typical applications. Atto Oxa12 shows excellent solubility in organic solvents like DMF, DMSO or acetonitrile.