The General Chemical Injector is designed to meter chemicals into your water stream downline of the pressure pump under low pressure. The advantage to doing this is that you don't run harmful, corrosive chemicals through your pump (they can shorten the life of your pump), and by applying your chemicals at low pressure, you reduce splash -- the chemical stays on the surface you're cleaning, and is allowed to work for you (less waste). This brass chem valve is a #2 assembly, and is rated at 4 - 6 gallons per minute at 3500 - 5800 psi working pressure @ 210 degrees max. An adjusting knob allows you to fine-tune your chemical mixture. Includes quick coupler, nipple, and a clear vinyl pick-up tube with intake screen.