The Pro-Series Hypercharger was designed for massive air-hungry V-Twin mills that like lots of RPMs. If your motor needs air, here's the place to start. The inlet is cavernous. The filter area has been increased by a full 50%. Internal shapes have been tweaked to allow increased flow & velocity. The ""Pro"" has a look all its own. All edges are radiused for a more streamlined appearance & a completely new cover with speed lines completes this picture of performance.