Vance & Hines Air Cleaner/Filter Duke Cover for Harley 04-08 It is all about how much air a motor can take in Here are systems that work better and look better than any other systems on the market An all-aluminum venturi in both designs helps shape the air for better flow Hand-formed steel covers for a distinctive look that is a perfect match for any Vance & Hines exhaust system Exhaust, fuel and now air is the complete the package