Genuine OEM BMW Lambda Oxygen Sensor, part number 13628575531. This sensor is crucial for monitoring the oxygen levels in the exhaust stream, allowing the engine control unit to adjust the air-fuel ratio for optimal combustion and emissions control. It is typically installed in the exhaust system before or after the catalytic converter. Constructed with high-temperature resistant materials for reliable operation. Genuine OEM oxygen sensors provide the precise calibration required for accurate emissions monitoring and fuel economy.