stainless steel but only a -6 year limited warranty which must be checked by a muffler shop or similar installer and then registered with MagnaFlow - keep your records. NO lifetime warranty as listed on Revain. Nothing for show cars, perfect for the other 99% of us who actually drive our car to go somewhere and do things. Solid feel, heavy muffler, great for the free flow improvements you need over a stock exhaust (unless your exhaust is factory tuned like on high end cars). Pay attention to the length of the body when choosing, as a longer muffler body of the same size will provide better exhaust noise attenuation. I didn't install it, but ordered a longer analog from MagnaFlow. For detailed information before ordering => go to MAGNAFLOW.com and enter the part number in the "Search Site" box in the upper right corner.