Dear,Please quote on below requirement.Cas No. :Zinc Sulte heptahydrate Zinc Sulte heptahydrate 21% crystal Molecular Formula:ZnSO4.7H2O, Molecular Weight:287.54 Appearance: white crystals, Content of Zn:21.0%min, Pb:0.002% max, Cd:0.002%max, As:0.001% max, Packing:25kgs plastic woven bag