K&N RX-4020-1 Universal X-Stream Clamp-On Air Filter: Round Tapered; 2.875 in (73 mm) Flange ID; 4.75 in (121 mm) Height; 4.25 in (108 mm) Base; 4 in (102 mm) Top Pleated filter built in top Washable and reusable Low restriction Clamp-on design