NO TOIL manufactures the world's best 2-stage foam air filters. Using only the best flame-laminated dual-layer foam bonded with the highest quality glue they hand make each foam filter to stand up to the roughest and toughest riding or terrain. NO TOIL filters can be used with NO TOIL biodegradable clean in water cleaner providing the best air filtration system in the world. Fits: Honda CRF250X 2004-2007 2009-2018 CRF450X 2005-2018