FOAM AIR FILTERS: 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 & 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 CR125R 1987-1988 CR250R 1987-1988 CR500R 1987-1988