Fitment: 1988-PRESENT SPORTSTERS (ALL MODELS) FITS BOTH CARBURATED AND FUEL INJECTED MODELS Eliminate the biggest restriction in a Harley Sportster engine for real HP you will feel. Features 4 Inch diameter filter. Billet Aluminum backing plate with internal breathing passages for super clean installation. Billet Aluminum face plate. Internal breathing system – clean installation – No hoses, No oil-catchers, no brackets. Filter is re-usable – simple wash, dry, and re-oil. Compatible with both carburated and fuel injected models. Don’t have to improve the ECU.