Boyesen s patented dual-stage design incorporates a specially shaped top reed and a ported bottom reed The top reed is lightweight and resilient for crisp throttle response at partial throttle or low RPMs. The stiffer bottom reed is ported to provide maximum flow and horsepower at higher RPMs More Air Flow. The dual-stage design allows you to replace your stock reed stop with a Rev-Plate which permits the reeds to open freely and function efficiently More Air Velocity. The multi-port feature of the bottom reed creates more channels for the charge delivering increased velocity to the intake ports More Overall Power. Dual-stage reeds work in unison to perform efficiently throughout the entire powerband. The difference in stiffness between the top reed and the bottom reed allow the reeds to respond quickly and accurately to changes in engine pressure. This translates into quicker acceleration crisper throttle response and increased horsepower throughout the powerband The price shown is for one set of reeds. Please check your vehicle whether you need one or two sets of reeds. Quicker acceleration for that all-important holeshot Crisper throttle response for fast corner exits and surer jumps More horsepower throughout the powerband for guaranteed performance Improved engine efficiency and fuel economy for the long distance rider Longer life - Boyesen Power Reeds outlast all other aftermarket reed petals NOTE: Certain models need to use the stock metal stops when installing the new reeds Fitment 1986 Honda CR80R 1980-1988 Kawasaki KDX80 1976-1983 Kawasaki KE175 1979-1985 Kawasaki KX80 1978 Yamaha DT100 1974-1981 Yamaha DT125 1974-1981 Yamaha DT175 1974-1975 Yamaha MX100 1979-1983 Yamaha MX100 1974-1981 Yamaha MX175 1990-1998 Yamaha RT180 1983-1985 Yamaha Tri Moto 125 YT125 1974 Yamaha YZ125 1981-1983 Yamaha YZ60 1975-1979 Yamaha YZ80