Twin Air 150209DC Dust Cover Fits: Honda CRF 250X 04-13, CRF250R 04-09, CRF450R 03-08, CRF450X 05-13 Fit this over your Twin Air filter when your riding in severe conditions such as heavy dust and sand This coarse foam pre-filter will act as an additional layer of protection Extends the service time between filter cleanings Designed for use with Twin Air air filters