POWERCORE 4: When designing the PowerCore 4, FMF looked at their top of the line products to deliver race-inspired performance at an economical price. The end result is a quality 4 stroke muffler with improved torque, increased horsepower and rugged durability all at a price that wont break the bank. Massive power gains throughout the RPM range Huge weight savings Rapid Tuning System (RTS) FMF uses the highest quality proprietary blend of alloy grade titanium made specifially to their standards Can be used with FMF or stock OEM header pipes We recommend all motorcycle parts are fitted and tested by qualified professionals. Fits: BETA RR350 4T EFI 2020-2021 RR350 Racing 4T 2020-2021 RR390 4T EFI 2020-2021 RR390 RACING 4T EFI 2021 RR430 4T EFI 2020 Beta RR 4T 350 2023 RR 4T 390 2023 RR 4T 430 2023 RR 4T 480 2023