51 12... Protective film for preventing paint abrasion in the area of the invisible joint (side frame)
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 (sourcing reference BMW Parts Department).
Installation note:
Protective film must not protrude over edge (5) of side frame (1) when being glued.