This air cleaner kit is designed to be used on Twin Cam engines equipped with H-D Screamin' Eagle Stage I air cleaner and the standard Twin Cam oval "football" style cover. It includes a specially designed, 100% washable pleated fabric filter made from multiple layers of surgical-quality cotton gauze material that traps the smallest dirt particles while providing dramatic flow increases. The element is 5/8" (1.6 cm) higher than the Screamin' Eagle element, providing 60% more filtering area than the Stage I filter. The kit includes required longer mounting hardware and takes about 5 minutes to install. The difference is immediately noticeable! It is not recommended to install it with decorative air cleaner cover inserts, as the increased weight may cause the filter to deform. Can not be installed with the stock 2006-up CVO Touring model oval covers as these do not make 360 degree contact between the cover back and the rubber gasket.