The best performance filters because of the special foam element, which allows more air to pass while providing good filtration. The heavy duty frames are injection molded and reinforced for long life. The choice of many European racing teams. The design allows for the use of air horns where applicable. One unit covers both carbs. Oiling Note: All ITG filters MUST be run with ITG specific filter oil (Dust Retention Spray or Heavy Duty Air Filter Oil) applied. Do not use K&N or other types of "filter oils" on ITG filters. The filter elements do not come pre-oiled from ITG, and the filter kits do not include oil to apply. Dust Retention Spray or Heavy Duty Air Filter Oil must be applied prior to their initial use, and after each cleaning. Air Horns Note: When using air horns, since the air cleaner must be installed last, it has to be installed "around" the air horns, as the brake and other underhood parts will interfere with simply attaching the filter. You may need to install the horns one at a time while positioning the filter.