K&N's custom air cleaner assemblies are designed with the racer in mind. They incorporate good looks as well as the superior air flow that you expect from K&N. These custom air cleaner assemblies are designed for use with any engine that uses a round element air cleaner housing. They incorporate our famous K&N Air Filters and provide more air flow than other assemblies of this type. Available in 4 different designs, the perfect assembly is sure to be found here. Each complete assembly comes with base, element, and top plate. These custom air cleaner assemblies are designed for use with engines that use a round element air cleaner housing. They incorporate our famous K&N Air Filters and provide more air flow than other assemblies of this type.