Check the listing for details. 1" NPT thread Muffler 304 Stainless Steel 2" x 9" exhaust Flex tubig Compatible.. Color: Silver, Condition: New. Listed at 54.50 USD. Muffler is made of 304 Stainless steel USA made.It is made of Thick SS Heavy duty Stainless steel,it won't break like the Chinese junk! You can use this muffler on any 1" female thread. common pipe thread or what they call black pipe thread. Universal uses, especially on minibikes and go karts!Muffler supports engines between 9-20HP Please understand that the 1" thread does not represent actual thread size, threads are measured as TPI number of threads per inch.Muffler is made of 304 Stainless steel USA made.It is made of Thick SS Heavy duty Stainless steel,it won't break like the Chinese junk! You can use this muffler on any 1" female thread. common pipe thread or what they call black pipe thread. Universal uses, especially on minibikes and go karts!Muffler supports engines between 9-20HP Please understand that the 1" thread does not represent actual thread size, threads are measured as TPI number of threads per inch.