Adjustable Fitting Universal Air Filter (RG-1001RD) by K&N K&N adjustable fitting Universal Air Filters are made with flange inserts which adjust the filter\’s flange to one of three inside flange diameters. The flange on these filters is made with ultra-strong molded pliable rubber which absorbs vibration and allows for secure attachment. K&N clamp-on universal air filters are washable and reusable. Features Designed to increase horsepower and acceleration Includes inserts to fit three different flange diameters High air flow with excellent filtration Clamp-on washable and reusable air filter Applications Universal Specifications Filter Shape: Round Tapered Filter Material: Cotton Gauze Height: 5.5 in (140mm) Base O.D: 6 in (152mm) Top O.D: 4.75 in (121mm) Flange Type: Centered Flange 1 I.D: 4 in (102mm) Flange 2 I.D: 3.5 in (89mm) Flange 3 I.D: 3 in (76mm) What\’s In The Box? 1 – K&N Universal Filter Warranty K&N 1-Year Limited Warranty