Sul-Po-Mag 0-0-21.5 Sulfate of Potash Magnesia (K-Mag)"Greenway Biotech Brand" 20 Pounds Potassium Magnesium Sulfate contains 21.5% Soluble Potash, 10.5% Magnesium, and 21% Sulfur It is derived from Sulfate of Potash-Magnesia Great source of Potassium, Magnesium, and Sulfur for you soil 20 Pounds If you buy it before 11 AM it is shipped the same day, otherwise next business day