K&N Engine Air Filter: High Performance, Premium, Powersport Air Filter: 1999-2012 YAMAHA (YFM400, YFM250 Big Bear, YFM250 Bruin, YFM400, YFM250 Bear Tracker, YFM400 Big Bear) YA-4001

ULTIMATE LONGEVITY: No-hassle lifetime limited warranty on stock replacement K&N air filters- limitations apply ENGINEERED POWER: State-of-the-art air filter media is designed to increase horsepower and acceleration as well as improve overall engine performance EASY INSTALLATION: Pre-oiled and ready to install. One of the easiest and most cost-effective upgrades for your motorcycle or ATV for quick performance gains. RUGGED CONSTRUCTION: K&N Air Filters are manufactured with durable, premium materials and state-of-the-art construction methods to last a lifetime