This product is a Genuine BMW Side Window Door Fixed Rear Left (Esg) - 51357317779. It is a replacement part for a BMW vehicle and is designed to fit the left side of the rear door. The product is made of high-quality materials and is an authentic BMW part. It is a fixed window and does not have any moving parts. This product is intended for use in repairing or replacing damaged or malfunctioning side windows on a BMW vehicle.