This item was the second item I have ordered from this company and both items meet or exceed my standards. This expansion chamber is made of polished thick metal. I highly recommend this product. I don't have to install it to tell you the benefits of this style of muffler but this model would be the best "BANG" for the dollar around here haha that's funny lol. SERIOUSLY, you take that damn loud expansion chamber, cut the end flush, take the one that came stock, cut it off and weld it together and you get the best performance another way. I trained as an auto mechanic for two years, grew up with a two-stroke engine and am 40. Haven't cut or welded yet, but the photo shows what I'm talking about. The last hole in the muffler "SHOULD BE INCREASED TO 1". Hope this helps someone. Use my trial and error on this project because I promise it will impress. I hope this is allowed.