HMF Honda TRX 450R 2007 - 2014 Competition Slip On Exhaust Muffler & Jet Kit UNI Three exhaust inserts are included to give the rider the ability to quickly change the power and sound according to the riding conditions. The Competition Series uses a mechanical core to control exhaust pulses and set power levels where they're needed. The exhaust shell is made of T6061 Aluminum that weighs substantially less than stock. USFS Approved: All HMF offroad exhausts come with a USFS approved spark arrester. Included: Individual Keihin Hex Jets: 135, 160, 165, 170, 48 Pilot