The Zimmermann Formula F is the answer to the riveted compound brake rotors introduced by original equipment manufacturers, which BMW uses in its F series and more. The compound rotor consists of an aluminum hub and cast friction ring. Enhanced thermal conductivity thanks to high-carbon casting provides a better braking performance. To cap everything the complete line is coated with "Coat Z – anti corrosion". Herewith we follow the demand for a more attractive visual appearance. ECE R90 approval for the entire range.