C.I. Direct Red 81; 7-Benzamido-4-hydroxy-3-((4-((4-sulphophenyl)azo)phenyl)azo)naphthalene-2-sulphonic acid; (3E)-7-(benzoylamino)-4-oxo-3-(2-{4-[(E)-(4-sulfophenyl)diazenyl]phenyl}hydrazinylidene)-3,4-dihydronaphthalene-2-sulfonic acid; 7-benzamido-4-hydroxy-3-[4-(4-sulfophenyl)azophenyl]azo-naphthalene-2-sulfonic acid