2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-[2-[4-[2-(4-sulfophenyl)diazenyl]phenyl]diazenyl]-, sodium salt (1:2)
C.I. Direct Red 81 disodium salt
Disodium 7-benzamido-4-hydroxy-3-({4-[(4-sulfonatophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonate