These non-electric, fluid-driven proportional injectors have the highest standard operating pressures in the industry! Here's how they work: Installed directly in the fluid supply line, the injector operates without electricity, using fluid pressure as the power source. The fluid drives the injector, which pulls the required percentage of concentrate directly from your chemical solution container. Inside the Dosmatic patented mixing chamber, the concentrate is mixed with the fluid and then the fluid pressure forces the mixed solution downstream. Like a hose end sprayer, the amount of concentrate will be directly proportional to the volume of fluid entering the injector, regardless of variations in flow or pressure. Use for: chlorination, cleaning, cutting fluids, descaling, degreasing, dispersants, fustigation, hydroponics, inhibitors, lubrication, medication, misting systems, odor control, pH/tH correction, rinsing, soaps and foams, surfactants. Model: MiniDos 120. 50% to 2.5% or 1:200 to 1:40 ratio