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.