For Mazda RX-7 Stainless Steel Catback Exhaust System With 4-Inch Dual Rolled Tip Made of high quality T-304 stainless steel. TIG welded CNC machine flange for resistance against pressure and corrosion. Aggressive deep and smooth tone sound while ensures smooth exhaust gas flow. Increase engine output and efficiency. 4 inch dual rounded muffler tip. Inlet diameter: 3 inch; outlet: 3 inch