2005-2008 Honda 400EX TRX400EX Red O-Ring Chain and Silver Sprocket 13/39 13 Tooth Front Sprocket, 39 Tooth Rear Sprocket and 520-94L Red O-Ring Chain All Race-Driven sprockets meet or exceed OEM specifications and use hardened S45C steel. O-Ring Chain helps keep the pins lubricated which reduces friction and helps the chain last longer. Fits 2005 2006 2007 2008 Honda TRX400EX