Factory 4.1 RCT Exhaust SystemRCT (Resonance Chamber Technology) features a patented core shape that lowers decibels while maintaining maximum power outputInternal ducts in the chambers of the RCT system increase internal volume for improved exhaust flow, resulting in power gains throughout the entire range of powerFMF's Factory Forward Engineering centralizes mass and is less prone to crash damageInnovative rear end cap features simple installation of tuning tip inserts or spark arrestor with the removal of four screwsMeets AMA and FIM sound requirementsQuietCore 94 dB insert includedMade in the U.S.A.