Direct Fast Grey BN

C.I.Direct Black 51

3-[[4-[(7-Amino-1-hydroxy-3-sulfo-2-naphthalenyl)azo]-1-naphthalenyl]azo]-2,6-dihydroxybenzoic acid disodium salt

3-[4-[1-Hydroxy-3-(sodiooxysulfonyl)-7-aminonaphthalene-2-ylazo]naphthalene-1-ylazo]-2,6-dihydroxybenzoic acid sodium salt