The K&N 20-21 BMW R18 1802cc Replacement Air Filter is designed to replace the factory air filter on BMW R18 1802cc motorcycles. It is made with high-quality materials and is designed to provide superior engine protection and performance. The filter is designed to improve airflow and increase horsepower and torque. It also features a washable and reusable design, which makes it easy to maintain and clean. The filter is designed to last up to 50,000 miles of use.