The FMF Factory 4.1 RCT Complete Exhaust With Stainless MegaBomb Header includes the following: FMF Factory 4.1 RCT Complete Exhaust: The Factory 4.1 RCT incorporates the latest in FMF Resonance Chamber Technology™ both internally and externally.
It starts at the center with a new core - a patent pending shape enhances and refines the exhaust pressure wave for optimal power output while lowering the sound level.
In addition, it achieves a shorter overall length that is less susceptible to crash damage and complementary to the Factory Forward Engineering - moving the muffler(s) closer to the motor to centralize mass.
Visible changes to the exterior include a redesigned canister to increase internal capacity for the maximum volume of packing material.
The packing itself was not overlooked - a proprietary blend formulated for superior durability and sound attenuation.

FMF - 2020 Yamaha YZF450 Complete Exhaust