K&N Replacement High-Flow Air Filters are The Original High-Flow Air Filter. Since 1969 K&N Engineering has been designing, manufacturing, and enhancing High-Flow Air Filters for the automotive and motorcycle enthusiast interested in maximizing horsepower and acceleration. Since K&Ns humble beginnings they have designed and manufactured over 2,400 High-Flow Air Filters to fit most modern passenger vehicles and over 500 High-Flow Air Intake Systems to fit vehicles driven by enthusiast minded drivers. K&N not only has more applications than any other manufacturer of similar product, K&N invented the High-Flow category and the High-Flow Technology that supports it. K&N also makes thousands of racing and specialty type air filters and is the only air filter used at the Indianapolis 500 Race.