Hiflofiltro HFF1018 Dual Stage Racing Foam Air Filter Fits: Honda CRF250R 04-09, CRF 250X 04-13, CRF450R 03-08, CRF450X 05-13 Competition off-road air filters manufactured in the Netherlands using a special dual-layer foam, formulated for maximum filtration and optimum air flow for improved power Coarse open-pore foam catches airborne dirt, grime and sand while the fine open-pore inner foam acts as a second filter to trap the smallest particles Top quality materials and superior construction allow the filter to be used over and over again without any loss of performance