PACESETTER HEADER, STEEL, BLACK, SOLD INDIVIDUALLY -- 1.625 in. tube diameter, 16-gauge tube wall thickness, 2 in. flange collector, 0.375 in. standard head flange; Gasket, reducer, and header extension included to connect to stock system; 4-2-1, two-piece style; Round head port; Easy-to-clean; Features mandrel-bent mild steel primary tubing that is black-painted to reduce underhood temperature and to resist rust and corrosion; Significantly boosts performance and increase engine efficiency; Hook-ups for smog and engine management sensors; Fabrication may be required; Pre-catalyst vehicles must use original emission control devices; It is the responsibility of the customer to reinstall these devices on the vehicle. Product legal for sale in California under Executive Order (EO) number D-439-5. Before purchasing this product, please check the Executive Order at www.arb.ca.gov to verify whether this product is allowed for installation on your specific vehicle application.