For Chevy Cavalier/Pontiac Sunfire 2.2L LN2 4-1 Stainless Steel Header/Exhaust Manifold Made of High Quality Stainless Steel with Computerized Mandrel-Bends for Strength and Durability i.e. Maximizing Smoothest High Exhaust Air Flow Rate 4-1 High Performance JDM Racing Spec. Design, Produces the Most Top End Power Offers the Best Flow Characteristics for the Engine at High Engine Speeds Increase High Flow Air, Instantly Gain 10 -15 Hp. / Tq. Inlet/ Outlet:1.5"(OD) / 2.25"(OD) / 16 Gauge Wall Piping / TIG Welded CNC Machine Flange / Metal Gasket Included