Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 517-21-5, Whether you call it Glyoxal bis(Sodium Hydrogen Sulfite) Adduct, Hydrate, 1 -2-Ethanedisulfonic Acid - 1 -2-dihydroxy- - Disodium Salt or 1 -2-Dihydroxy-1 -2-ethanedisulfonic Acid Disodium Salt you can be assured the Glyoxal bis(Sodium Hydrogen Sulfite) Adduct, Hydrate products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.