This product is a Genuine BMW Moulding Rocker Panel designed for the rear left side of the vehicle. It is part of the M line, which is BMW's performance division. The product number is 51127902991. This moulding is made specifically for BMW vehicles and is a high-quality, OEM (original equipment manufacturer) part. It is used to protect the lower part of the vehicle's body from damage and also adds a stylish touch to the car's appearance. It is a durable and reliable product that is designed to fit perfectly on the vehicle.