HMF Exhaust Titan Series: Virtually the entire exhaust system is built from 304 Stainless Steel. It doesn’t readily corrode, rust or stain and it can reliably withstand the extreme temperatures generated from high performance off road vehicles. The sound from the Titan is a deep and aggressive, adding depth to the machine’s sound. This relieves some of the high pitch sounds created from the stock system. The Titan-QS features a mechanical core design that produces incredible horse power while keeping the sound levels to a minimum. For the riders out there craving maximum horse power with maximum volume, the Titan-XL features an unrestricted internal core design that produces maximum horse power at an incredibly loud volume. These exhaust shells are big, and so is the performance they create. The 5″ inch diameter exhaust shells house an internal exhaust core that creates maximum airflow. When stacked into a dual system, it creates even more power and performance while improving sound. Free spark arrestor with each muffler ordered!