This is the first carbon fiber velocity stack that I have seen. But the interesting part is that it includes a unique mounting ystem allowing adjustment to fit any HD or aftermarket V-Twin engine. It is available for all Evo and Twin Cam type engines with S&S E or G and Mikuni HSR 42/45 and stock Keihin carburetors. Note also the unusual "flat" design. From Sansone Motorcycles.