The SHW cross-drilled lightweight brake rotor for 2018–2021 BMW M5 4.4L (left rear) is a vehicle-specific replacement identified for that engine and wheel-side. This drilled, lightweight rotor is sold as the left-rear unit with the catalog reference included to aid part verification and support a like-for-like replacement on the listed M5 rear-left position.
SHW 18-21 BMW M5 4.4L Left Rear Cross-Drilled Lightweight Brake Rotor (34217991103)