RACING K&N AIR FILTER Designed to allow high airflow with virtually no restriction, K&N air filters are guaranteed for 10 years or 1 million km. They consist of 4 to 6 layers of cotton mesh placed between 2 aluminium mesh plates. The cotton is then pleated and oiled to enhance its filtering capacity and overall performance. LARGER FILTERING SURFACE FOR OPTIMISED AIRFLOW For over 30 years, K&N has been manufacturing high-quality air filters.