Ferrous Sulfate Heptahydrate 20% Iron (Fe) 12% Sulfur (S) 100% Water Soluble Powder"Greenway Biotech Brand" 10 Pounds 10 Pounds of Greenway Biotech Ferrous Sulfate Heptahydrate 20% Iron (Fe) 12% Sulfur (S) 100% Water Soluble Powder Required for the Formation of Some Proteins as well in Photosynthesis Promotes Healthy Growth in Plants and Energy Transfers Part of the Enzyme System Needed for Plant Respiration Essential for Chlorophyll Production