I bought this for my 2021 500EXC-F. It replaced the stock muffler with a billet end cap. The weight savings over the stock muffler is noticeable. The sound is awesome, not too loud but more aggressive than the muffler it replaced. Not nearly as loud as a 450sxf. Also, there was a noticeable increase in torque. 4th gear clutch ups are effortless now. I really wish Arrow made a titanium header to match instead of the stainless, hopefully in the near future.