Vehicles with gasoline engines are the past few years equipped as standard with a catalyst (also called catalytic converter) and reducing harmful emissions. The lambda probe is a sensor playing a decisive role in this process of clean-up : it enables the catalyst to function optimally. Equipementier leader in original equipment and the aftermarket, independent, NGK Spark Plug continues to develop and improve its range of Lambda sensors to allow the engines to be cleaner and more efficient, and thus contribute to a better air quality.