K&N ATV Air Filter + Oil Filter Combo 1999-2008 Honda TRX400EX HA-4099 + KN-113 Designed to boost horsepower and rate of acceleration Specifically developed for Off-Road, Motocross, ATVs, UTVs and Side by Sides Pleated cotton media provides a large filtration area offering low restriction, high-capacity and long service intervals Multiple layers of woven cotton gauze media offers excellent filtration Fits directly into OEM air box with application specific sealing bead ensuring a precise fit