... well-known manufactory in China, 1,Specification For Food Grade and Industry Grade:ItemQuality IndexFood GradeIndustry GradePurity(As Na2S2O5)98.0%min96 ... -4.8Remark:Cinformed with FCC V and E223 Standard2,Photo Grade and Pharmaceutical GradeItemQuality IndexPharmaceutical GradePhoto GradePurity(As Na2S2O5)98%min98 ... .84.0-4.8RemarkConformed with USP standard Sodium metabisulphite industrial grade