Works well for vehicles with cat-control function to avoid an error in the system in general. (Please note that a 100% guarantee can�t be given that the cat monitoring of your vehicle does not report any errors!) optionally: Oxygen-Sensor-Emliminator / Spacer ( 45� ) with integriated ceramic-mini-catalyst 600CPSI and EU5 coating. or Oxygen-Sensor-Emliminator / Spacer ( 45� ) with integriated metall-mini-catalyst 300CPSI and EU6 coating. We offer this part exclusively for motor sport vehicles outside the StVZO. By purchase, you confirm that you are not using this item for a vehicle that is used on public roads.