A wide variety of standard pipe thread connection pressure washer chemical injectors. We stock various types, including variable and non-variable injection rates, and also offer injectors made for acid application and more. These injectors utilize standard 3/8" pipe thread (NPT) connections and install between the pressure washer pump and the pressure washer hose. It is used to inject soap or chemicals downstream from the pump to prevent seal damage. Under low pressure, the soap or chemical is drawn into the water flow but automatically shuts off under high pressure.