All Vibrant Performance merge collectors feature complete T34 Stainless Steel construction, precise fabrication, top quality TIG Weld and hand porting inside the collector for smooth, unobstructed exhaust flow. All Vibrant merge collectors include a min. 3" long transition outlet cone Dimensions: -----------Inlet Slipover ID 2.25" Merge Outlet OD 3.5" Transition Cone Outlet OD 4"