Mikuni Hs40 Air Intake Adapter for Enabling the fitting of a (Sold Separately) HSR42 CV/S&S Air Filter Adapter When pressed on this adapter allows the fitment of the HSR42 air filter adapter Allows a HS40 to fit any Harley davidson CV air cleaner when using a HSR adapter (not inc.) Gives HS40 owners the the freedom of air cleaner choice Some S&S air-cleaner backing plates require modification when fitting This is an essentual part of the Mikunioz Shovelhead Kit (bought separately)