These resonators are used to convert a 140632 S-Type system into an ATAK(r) system. Use ONLY with Borla(r) system. It does NOT fit competitors or Original Equipment systems. 2.75" diameter part. Built from premium T-304 stainless steel, superior to T-400 series (such as 409), to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, Borla(r) stands behind every direct fit resonator with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.