GiroDisc 2-Piece Front Rotors for B9 S4, S5, and SQ5 are high-performance rotors from proprietary high-carbon steel casting. They feature 72 curved vanes to help dissipate heat and a 2-piece design with a reusable hat. The hats are made from 6061-T6 aluminum and coated in a black anodized finish, while the drive pins are made from a high-strength steel alloy and cadmium-plated. All rotors are assembled with spring clips and Belleville washers for race-ready float while also street-friendly with no noise from loose hardware.