Pro Circuit R304 Shorty Silencer - Aluminum Used by practically every PC-equipped motocross professional on the podium today Housing is made of lightweight 6061 T-6 aluminum with brushed finish that is not only stylish but also guards against damage High-strength aluminum rivets and steel Allen head screws on one end for easy disassembly and repacking Other features include a 304 stainless intake tube Double-walled mounting brackets