Quiet cap ONLY fits AA slip-on exhausts with dual 2.5" outlets - Does NOT fit OEM exhausts or AA exhausts with 2" outlet Fits into one of your outlets (cannot be ran in both outlets) which makes sound waves bounce inside that tube and reflect back, making it quieter than a single outlet exhaust. Because of our exhaust design, this quiet cap does not reduce flow or horsepower on any 900 or 1000 motors, and does not reduce horsepower on turbo models until running over 21 PSI of boost. Lowers sound by roughly 5-7 dB Installs with 2 bolts in only a few seconds Includes the black anodized stealth cap, bolts and lock washers PN: 111-1001