FATTY PIPE: With well over 35 years of racing experience behind it, the Fatty Seriespipe delivers race proven performance. The Fatty broadens and smoothes out the power curve while boosting gains throughout the entire power band, more low-end, more mid, and increased over-rev. No matter what type of riding you do, the Fatty has the benefits youre looking for. More tractable power, improved throttle control Provides power gains throughout entire power band Carbon steel with a nickel plated finish for maximum durability FMF Racings Tru-Flo stamping process ensures a perfect fit and optimum performance Can be used with FMF or stock silencer (unless noted) FMF'S most popular 2-stroke pipe O-Rings included Fits: Yamaha YZ125 2005-2021 YZ125X 2020-2021