Check the listing for details. HMF Honda 400EX Muffler 400 EX X Slip on Exhaust Pipe Atv 400X 1999-2014. Condition: New. Listed at 389.95 USD. Honda 400EX 400X HMF Sport Performance Series Slip on Muffler FitsHonda 400EX All Years 1999-2014 Brushed Finish Brand - HMFManufacture # 019253606071 The Honda TRX 400EX exhaust mufflerEach series Slip On exhaust picks up 10-15% more horse power and torque throughout the power curve. The mufflers will be roughly 4-6 dB louder than the stock exhaust, Optional HMF Quiet Core can reduce that 2-6dB.HMF Engineering Performance Series Slip-On ExhaustHMF exhaust comes with a U.S.F.S. Spark ArrestorBrushed Aluminum finishDesigned for 4-stroke machines with 304 stainless steel headers and inletsT-6061 aerospace-grade aluminum shellsHeavy-duty stainless steel rivetsTwo-year manufacturer warrantyTIG welded aluminum bracketsTwo-piece billet end caps that accept a USFS-approved spark arrestor andthe exclusive HMF quick-change low dB Quiet CorePacked with Bristol Core brand pillow packingTurndown end cap1999-2014 Honda 400EX HMF Sport Performance Series Slip on Muffler