Bought this product for two reasons. One, for the spark arrester and two, to quiet a KX65 down so my son could ride around our house without upsetting the neighbors. I assume the spark arrestor works and will legalize the bike for state and national parks. The silencer did not quiet the bike down as hoped. It did take some of the sharpness out of the exhaust but it's still loud. However, the tailpipe offers a spot to clamp on a short piece of bicycle innertube which decrease the sound a little more But this lowers performance and its harder to keep the bike at idle. The muffler is well made, looks good and installed easily. And as far as I can tell the muffler by did not change performance of my sons Kawasaki KX65.