Sodium Metabisulphite in Free Flowing Crystalline Form contains assay in a minimum amount of 96%. Sodium Metabisulphite is offered in free flowing crystalline powder form with odour of sulfur dioxide. Sodium Metabisulphite comprise of maximum 15 PPM iron and 10 PPM heavy metal. Sodium Metabisulphite in Free Flowing Crystalline Form contains balanced amount of sulphate.