The BMW E83 X3 is known for its excellent braking, but brake discs become thin and worn over time, reducing their effective performance. These Zimmermann discs come with their own 'Coat Z' anti-corrosion treatment to stop the discs from developing rust patches, as is common with rotors. The Zimmermann brand is highly regarded in the industry and is an original equipment supplier of braking components to BMW. Made in Germany.