Powerflex Black Series Car: BMW - F20, F21 (2011 -) description: Ride Height Adjuster Shim purchased parts package: 1 installation location: rear notice: PFR5-427BLK is designed to adjust known ride height issues found on right-hand vehicles by increasing the thickness of the original part to 11.4mm or can be used on each side to increase overall ride height. Part no.: PFR5-427BLK