4 1 SS Merge Collectors (2 Inch Inlet Slipover ID, 3 1 2 Inch Merge 2 1 Steel Exhaust Merge Collector Dual 1.5" ID Inlet Single 1.75" OD Vibrant 2 1 SS Merge Collectors (2 1 2in Inlet Slipover ID 3 1 2in Vibrant 2 1 SS Merge Collectors (1 7 8in Inlet Slipover ID 2 1 4in Outlet OD) Sold Individually Vibrant 2 1 SS Merge Collectors (2in Inlet Slipover ID 2 1 2in Outlet. Vibrant Performance has developed a comprehensive, high quality and Affordably priced range of 304 Stainless Steel Merge Collectors to help our customers free up maximum horsepower from their exhaust setup. For many years, merge collectors were almost exclusively used by top professional race teams. However, this proven technology is now commonly used at all levels of professional racing (where rules permit) and now many fabricators are incorporating merge collectors into street header applications.