Sodium Metabisulfite is used for both its sterilization and stabilization effects.  It contains the Na (Sodium) ion, as opposed to the K (Potassium) ion and will impart Na if added directly to wines or juice.  It is not approved for use in wine commercially, but otherwise can be used in lieu of potassium metabisulfite.  Musto recommends this product be used for sanitization and Potassium Metabisulfite for stabilization.

Dosage (sanitization): 2 tablespoons per gallon.