The RS-4 muffler’s design shape helps centralize mass. Its poly-resonant duplex chamber increases overall power while reducing sound. It is available as a full system, in either titanium or carbon fiber, or as an aluminum slip-on. The RS-4 features an ultra-lightweight carbon fiber end-cap, and 2 meter max, 94 decibel and spark arrestor inserts are available. The RS-4 is available for most late model 250 and 450cc MX bikes.