I think it's just plastic. I'll give a brief description- first off the car is a Lexus, the lowest on the chain of fine automobiles, it's a large section where the side and back of the car meet, but below the actual bumper. It seems to be an "extension of the bumper. I hope that helps and yes I am a dumbass when it comes to cars and their parts. I do appreciate your help. Thanks.
rogie