HMF 141403706186 Competition Exhaust: Yamaha YFZ 450 Fits: 12-13 Slip On Elliptical Side mounts Euro-Polished End Cap Equal Power: The Competition Series distributes power evenly throughout the entire RPM range Variable Sound: Three exhaust inserts are included to give the rider the ability to quickly change the power and sound according to the riding conditions Mechanical Core: The Competition Series uses a mechanical core to control exhaust pulses and set power levels where theyre needed.