TWIN AIR PRE-OILED AIR FILTER - Honda CRF '13-'17 - 150221XDescription: Each Twin Air filter is pre oiled with Twin Air biodegradable foam filter oil, developed exclusively for Twin Air by Chevron Texaco. Independently tested by the most prestigious engineering lab in Germany and was found to be the superior filter oil on the market. Features: Coarse open pore foam catches airborn dirt, grime and sand Fine open pore inner foam acts as second filter to trap the smallest particles while ensuring maximum air