HMF 041413706071 Performance Exhaust: Yamaha YFZ 450R-X Fits: 09-14 Slip On Elliptical Side mounts Turn-Down-Brushed End Cap EQUAL POWER: The Performance Series distributes power evenly throughout the entire RPM range. 4-6 dB INCREASE: Depending on the model, you can expect a 4-6 dB increase over stock. UNRESTRICTED CORE: The Performance Series uses a 2 1/8 non-restrictive core for maximum flow.