4-hydroxy-6-[methyl[[2-(sulphooxy)ethyl]sulphonyl]amino]-3-[(4-sulphophenyl)azo]naphthalene-2-sulphonic acid, potassium sodium salt

4-Hydroxy-6-[methyl[[2-(sulfooxy)ethyl]sulfonyl]amino]-3-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid/sodium/potassium,(1:x:x) salt