Genuine OEM BMW Lambda Oxygen Sensor, part number 13628589665. This sensor is essential for measuring the oxygen content in the exhaust stream, allowing the vehicle's computer to adjust the air-fuel mixture for optimal combustion and emissions control. It is typically mounted in the exhaust pipe. The sensor is engineered with durable materials to withstand the high temperatures and corrosive environment of the exhaust system. Using a genuine OEM Lambda Oxygen Sensor ensures the correct calibration and performance characteristics required for efficient engine operation and environmental compliance.