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 a patented internal hidden breather backing plate technology relieving the need for external hoses or hardware for a virtually closed loop system. Radius air inlet provides unobstructed airflow into engine. High performance filter is constructed from red pre-oiled cotton for optimum flow and filtration. Filter is washable and re-usable, recharge kits available separately.