Cobras award winning slip-ons for Goldwing Models are loved by man in the industry including real world riders alike. It's due to Cobra being able to offer increased horsepower and torque with a more aggressive exhaust note. These 4" muffler offers proprietary technology to prevent bluing from occurring. As the louvers in the baffle are positioned further back within the muffler, gasses have the chance to cool before leaving the silencer core making the 4" Billet Scalloped slip-on mufflers virtually blue proof.; Adds just the right sound to your Gold Wing Deep and mellow with just the right note Simple slip-on installation and Cobra limited Lifetime warranty