Mazzei Venturi Injectors provide a simple, accurate and reliable way to inject fertilizers and other chemicals into your irrigation water. With no moving parts or external power required, the flow of your irrigation water across a venturi chamber creates a suction force that draws a chemical out of a storage container and into the water flow. A metering valve on the suction line accurately controls the injection rate and injection automatically stops whenever water flow stops. A spring loaded check valve ensures water never backflows into the chemical tank.