This product generates twelve grams of chlorine dioxide gas dissolved in water. To initiate generation, simply immerse the product in the water. The concentration is volume dependent. For example, the 12G will produce a 100 ppm (0.01%) solution in 120 liters. The sachet can be used as a single unit, or in multiples to produce larger volumes or higher concentrations. For all the details, download the 12G datasheet.