Invidia (HS12HC4STT) N1 Titanium Tip Cat-Back Exhaust System for Honda Civic Si Sedan Fits 2012-Up Honda Civic Si Sedan Pipe size: 76mm (3"), Tip size: 101mm (4") Constructed with high-quality SUS304 stainless steel, CNC-machined flanges, and manufactured with a polished finish Mandrel-bent stainless steel piping for maximum exhaust flow and reduced back pressure Single Titanium Tip