The Genuine BMW Auxiliary Fan Assembly - 64546921395 is a replacement part for a BMW vehicle's cooling system. It is designed to help regulate the temperature of the engine by circulating air through the radiator. This assembly includes the fan motor, blades, and housing, and is a genuine OEM (Original Equipment Manufacturer) product made by BMW. It is specifically designed to fit and function properly in BMW vehicles and is made with high-quality materials for durability and reliable performance.