The Genuine BMW Seal Outer Left Mirror Triangle is a part used in BMW vehicles to seal the outer left side of the mirror triangle. It is designed to fit perfectly and securely in place, providing a tight seal to prevent any water or debris from entering the mirror assembly. This seal is made from high-quality materials to ensure durability and longevity. It is an essential component for maintaining the integrity and functionality of the left side mirror on a BMW vehicle. The part number for this seal is 51337317917.