Genuine OEM BMW Oxygen Sensor, part number 11781437943. This sensor measures oxygen levels in the exhaust stream, providing critical data to the engine control unit for optimal fuel-air mixture and emissions control. It is typically installed in the exhaust manifold or pipe. The sensor features a durable construction with a threaded mounting point and a multi-pin electrical connector. Genuine OEM ensures precise calibration and reliable operation, vital for maintaining engine performance and meeting emissions standards.