Genuine BMW Impact Sensor Left (525i 545i 530i 645Ci) - 65776974364: Genuine BMW Impact Sensor Left (525i 545i 530i 645Ci) - 65776974364 is a high-quality OEM replacement part designed to fit perfectly with your BMW vehicle. It is designed to detect impacts and provide feedback to the vehicle's computer system to help ensure your safety. It is easy to install and is constructed of durable materials to ensure a long service life.