The k&n high-flow air filter is designed to achieve high, virtually unrestricted air flow while maintaining filtration levels critical to ensure long engine life. Our automotive oe (original equipment) replacement air filters generally add 1-4 horsepower. The secret to our success lies in the unique characteristics of our filter medium that was originally developed by k&n all those years ago in the dust, sweat and tears of desert motocross racing. We just wanted to win races and stumbled on a cotton filtration technology destined to be great. Our high flow cotton gauze air filter is washable, reusable and built to last for the life of an automotive or motorcycle engine. K&n air filters consist of four to six sheets of cotton gauze layered between two sheets of aluminum wire mesh.