The most reasonably priced component used on the Trx90ex8 Sportrax90 2008 (8) Australia Exhaust Muffler is the Washer,plain, 6mm.
The Exhaust Muffler assembly is constructed from several parts from which the Muffler Comp is the most expensive.
This schematic depicts all components used in the Trx90ex8 Sportrax90 2008 (8) Australia Exhaust Muffler partslist.