51 12... Protective film for preventing paint abrasion in the area of the invisible joint (side frame)
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2015 BMW Alpina B7L xDrive, 2015 BMW Alpina B7 xDrive, 2015 BMW 750i xDrive, 2015 BMW 750Li xDrive, and 2015 BMW 740Li xDrive. However, it is still accessible from the selected car via links, so may be relevant.
To prevent paint abrasion between rear bumper trim (3) and side frame (1), protective film (2) and (4) should be glued in the area of the invisible joint.
Protective film (2) is a shaped part, protective film (4) is a foil strip.
Installation note:
Protective film must not protrude over edge (5) of side frame (1) when being glued.