K&N E-3180 Round Air Filter 5-7/8"OD,4-1/2"ID,1-3/4"HDescription K&N E 3180 Round Air Filter 5 7 8"OD,4 1 2"ID,1 3 4"H K&N washable, reusable High Flow Air Filters feature a layered, oiled cotton media designed to improve airflow and capture contaminants. These filters are engineered to provide an increase in horsepower and are built to last for the entire lifespan of the vehicle. Each performance air filter is reusable and installs easily into the factory air box. K&N drop in replacement filters are