Parts & Accessories Spare parts In the name of God, the Most Gracious, the Most Merciful. I have a catback and WAI, both custom-made by Garage Al Ain. The WAI and kit are 3 inches and fit the stock headers. The original Skyline electronic muffler, which is Fox, is 3 inches with its blue device and two remotes. And an outlet that looks like the stock one. I used it for 4 months, and there are no leaks or cracks. Just check the valve before installing it. Best offer #GMC #Sierra #Catback #Tuning #Exhaust