Reduces stalling Smoother, more controlled and tractable power delivery Better traction Easy installation Available in 8, 10, or 12 ounces Made in USA This easy mod will make it much easier to control the hard hitting power of the little KX. Most woods and trail riders will benefit. All beginner and timid riders will do better with the smoother power and less stalling that will reduce frustration and fatigue. Quick and easy installation, without any drilling, grinding or welding. The engine lock up tool (E-3) will make it even easier. Add 12 ounces for timid or beginer trail riders. 10 ounces for intermediate trail riders or timid MX riders. 8 ounces for aggressive trail riders or intermediate MX riders