The FMF Turbinecore 2 spark arrestor silencer is their best selling silencer for FMF because of their reputation of quality performance enhancing design. The FMF Turbinecore 2 silencer has earned the U.S. Forestry stamp of approval with the built-in spark arrestor in addition to the FMF exclusive "Turbinecore Dampening System." The Turbinecore 2 silencer is a straight-through design that is less restrictive than stock for great track and trail performance. FMF constructed the Turbinecore 2 silencer out of stainless steel to withstand all the stress of the aggressive riding you can put it through. Match the FMF Turbinecore 2 silencer with a FMF pipe to maximize the potential of your bike. The best-selling Turbinecore 2 uses the exclusive "Turbine Dampening System." This top-notch product has well-earned its U.S. Forest legal status.