The FMF Q has always been in a league of its own and the latest Q4 is the most significant upgrade to date. You don't need to settle for a plugged-up moto muffler hampered by an insert when you can have a compliant muffler engineered for performance. Less sound equals more ground. Meets U.S.F.S. and FIM World Enduro sound regulations. Power gains throughout the entire RPM range. Spark arrestor included. Pounds lighter than stock. Rugged design for off-road endurance. Only U.S. manufacturer to offer dedicated quiet exhaust systems. Can be used with FMF or stock O.E.M. header. Made in the U.S.A. Note: For closed course competition use ONLY. Not intended for street use. Detailed Specifications: Type: Slip-On. Configuration: Single. Construction: Aluminum. Finish: N/A.