Arlen Ness AN-18-968 Method Air Cleaner Kit Black for Sportster 88-21Arlen Ness Black Method Clear Series Air Cleaner 18 968 Forged billet aluminum air cleaner featuring a polycarbonate window allowing you to view the internal working of your air intake system Forged billet aluminum backing plate with our patented internal hidden breather backing plate technology resulting in no need for external hoses or hardware for a virtually closed loop system Radius air inlet provides unobstructed airflow into engine High