GYTR® Performance Oval Muffler Design based on our Factory team motocross pipes. Offers improved power throughout the power band: 25% increase in low-end horsepower, 20% increase in midrange horsepower and a 5.5 peak horsepower gain. 3.5 lbs. lighter than stock. Features include: Hard anodized aluminum shell 6061-T6 aluminum two-piece end cap Stainless steel inlet pipe New fixed rubber mounting system Removable screen-type USFS-approved spark arrestor Completely rebuildable *This accessory may be restricted to closed-course use. This accessory affects emissions; installation on EPA-regulated 2007 or later models constitutes unlawful tampering except when used solely for closed-course competition. This performance accessory does not meet California standards for off-road recreational vehicle usage. Fits '04~'09 YFZ450 GYT-5TG93-02-AL $367.95