Strict emission limits require the best possible exhaust gas cleaning. The SCR system commonly used in diesel engines requires the injection of a urea solution into the exhaust gas stream. In certain vehicles, diesel injection into the exhaust gas stream is also used to regenerate the diesel particulate filter (DPF). Hirschvogel produces housings in various versions to accommodate such metering modules for urea solutions or diesel fuels. Stainless steel grades are used to ensure long-term function under corrosive conditions.