K&N Engineering Universal Round Tapered Air Filter - Rubber End Cap R-1100When selecting one of K&Ns universal round tapered air filters, you should consider the following dimensions as they relate to the specification chart: Mounting Flange Inside Diameter This is the most critical dimension and should be very close to the diameter of the applications inlet flange The flange will stretch up to 1 8in. for those in between sizes Filter Diameter This is the outside diameter of the filter. The top size is listed first, then