For Ford F-150 High Performance 3-1 2-PC Stainless Steel Exhaust Header Kit - 4.2L V6 Made of High Quality T304 Stainless Steel for Strength & Durability TIG Welded CNC Machine Flange for Percision & Fitment Offers the Best Flow Characteristics for the Engine at High Engine Speeds Increase High Flow Air, Instantly Gain 10 -15 Hp. / Tq. 1.5" Inlet / 2.25" Outlet / EGR & O2 Sensor Bung Insertion & Gasket Included