As the pioneer of quiet performance mufflers, FMF raised the bar again in 2007 with the second generation of Q series mufflers, the Q4. Built from the ground up, the Q4 is a completely new design, engineered for maximum performance while maintaining a sound level at or near 93dB on most models. The Q4 is the market leader for low sound / high performance. Less sound equals more ground. The Q4 incorporates Factory Forward Engineering to move the muffler closer - centralizing the mass for improved handling characteristics. The new Hi-Flo formed end cap reduces weight and is less prone to damage. The Q4 has an anodized aluminum canister and is lighter and quieter than the original Q model slip-on. All Q4 exhausts utilize a maintenance-free U.S.F.S.-approved turbine type spark arrestor so there is no screen to clean or burn out.