This SHW cross-drilled lightweight right rear brake rotor is listed for 2021 BMW M3 and 2021–2022 BMW M4 applications. The rotor combines cross-drilled vanes and a lightweight construction stated in the title to reduce unsprung mass and aid heat dissipation during repeated braking events. It is offered as a direct-fit right rear replacement matching the OEM-style fitment called out in the description.
SHW 2021 BMW M3 / 21-22 BMW M4 Right Rear Cross-Drilled Lightweight Brake Rotor (34208093730)