Arlen Ness 10-Gauge Stage 1 Big Sucker Air Cleaner Kit For Harley Unleash your engine's potential with the Big Sucker, engineered to deliver maximum airflow and performance. Testing shows that with a Big Sucker kit, you can achieve up to a 21 increase in horsepower. The kits incorporate patented hidden breather backing plate technology, meaning the breathers are built into the air cleaner housing itself, removing the clutter of external hoses and hardware. The stainless jacketed air filter, made from a water-resistant synthetic material, never requires oilingjust wash and reuse. Features: Billet aluminum backing plate Integrated crankcase breather for a clean look Built in velocity stack for increased performance Synthetic filter element never needs oiling