Arlen Ness 18-921 Black Inverted Series Air Cleaner Kit The ultimate combination of performance and design for your V-Twin engine Inverted pleated top with pleated sides to maximize airflow Our pre-oiled Black filter element is encapsulated in a Stainless Steel jacket for the ultimate in style and durability Forged air filter housings feature built-in velocity stacks that scream performance and enhance looks Forged billet backing plate features our proven radius inlet, hidden Breather hardware and our industry leading Big sucker patented technology