Fits all fuel injected Harley-Davidson® Sportster® motorcycles.  This unit allows for more airflow over the stock 45mm throttle body.  Kit includes a Billet-Pro air cleaner equipped with a custom air filter element (carbon fiber cover sold separately).  Designed to improve horsepower gains between 8-10hp depending on other build modifications.  51mm and 55mm throttle body sizes available with CNC ported intake runner diameters for 1.620 and 1.710 dimensions.