1 5/8" diameter, 14g primary tubes, 3/8" thick laser-cut flange with a 2 1/2" ball & socket collector, adaptors included. Requires cutting and welding for proper installation. 50 state legal EO# D374-3. For 6.0L applications with or without an EGR system. Connection port, gasket and block-off plate (for unused ports) provided. Ceramic Coated.