Yoshimura RS-9 Enduro Exhaust System - Aluminum Muffler 24140AH320Diamond shape muffler canister design improves power output Muffler shape increases durability and performance from muffler packing Comes with 96 dB U. S. F. S. approved spark arrestor insert Muffler sleeve features a brushed aluminum finish To avoid blueing, consider properly tuning the vehicle; however, the vehicle must always remain within the legal standards for emissions controls as defined by EPA, CARB and any other applicable state laws.