With well over 35 years of racing experience behind it, the Fatty pipe 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 you're looking for. Features: More tractable power, improved throttle control Provides power gains throughout entire power band Carbon steel with a nickel plated finish for maximum durability FMF Racing's Tru-Flo stamping process ensures a perfect fit and optimum performance. Can be used with FMF or stock silencer (unless noted) Our most popular 2-stroke pipe O-Rings Included Fitment: Yamaha YZ250 1999-2021 Other Part Numbers: FMF Racing #78-1359