Yamaha GYT-5NLPA-CK-NG GYTR Muffler Packing Cartridge for Yamaha YZ426F Round GYTR muffler kit; fits 13 inches muffler for '01-'05 and '10-'11 YZ250F, '01-'06 WR250F also fits '00-'02 YZ426F and WR426F