Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 7681-57-4, Whether you call it Sodium Metabisulfite, Disodium Disulfite , Disodium Pyrosulfite , Sodium Metabisulphite or Sodium Pyrosulfite you can be assured the Sodium Metabisulfite products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.