RSD Venturi Air Cleaner Slam BLK OPS for Harley FLH/FLT 08-11 Exposed filter design that enhances airflow Backing plate promotes smooth airflow into carburetor/throttle body Built-in internal crank case breathers Contrast Cut finish starts with a polished venturi air cleaner faceplate that has been black anodized, then recut to open up the design Platinum Cut uses the same process as the Contrast Cut, but the recut areas are hand polished to a brilliant shine