indigo blue(vat blue 1),vat dyes. 1)Appearance: Dark blue even powder/granular 2)Strength:100 3)Moisture%:1.0max. 4)Fe3+: 200ppm max 5)Packing: in 25 kg net bag/iron drunm/net carton 6)Application: As dyestuff,be mainly used to dye cotton fab