K&N washable, reusable High-Flow Air Filters for the BMW X3M F97 & X4M F98 feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide an increase in horsepower. Each performance air filter is reusable, engineered to last for the entire lifespan of your vehicle, and backed by K&N's 10-Year/Million Mile Limited Warranty. K&N drop-in replacement filters are designed to install easily into your factory air box. Upgrade today and start enjoying superior airflow and superior performance from K&N's most popular product to add performance to your BMW S58 engine.