Features 16-gauge steel construction throughout. 1 -3/4″ headpipes flow into 2 -1/4″ muffler bodies for increased flow and improved performance. Designed to increase low-end torque and produce a deep, throaty exhaust note. Includes heat shields for the headers, mounting brackets, hardware, O2 sensor ports and plugs. Made in the U.S.A.. Includes 12 mm and 18 mm O2 sensor ports.