Yoshimura Sound Insert Kit 94Db Rs-4S Muffler, 1.375" (Ins-18-K)Yoshimura Sound Insert Kit 94Db Rs 4S Muffler, 1. 375" (Ins 18 K) Replacement Low Volume Insert Kit for RS 4 "Turn out End cap" Mufflers Non Spark Arrested Available as optional kit on applications requiring different sound restrictions Decibel reduction depends on application Kit Includes: Low Volume Insert Tube End cap collar Set screw This product was designed to fit on a standard equipped motorcycle, as delivered from the factory. OE and