This Resonator is designed to replace the Merge X-Pipe in select BORLA® 140590 and 140591 Cat-Back systems to dampen the sound. It is NOT designed to work with competitors or Original Equipment (O.E.) systems. The resonator contains an internal H-Pipe for increased performance and improved sound. Dual 2.25" diameter inlets, dual 2.5" outlet. Resonator features an internal H-Pipe for increased performance and improved sound. 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. Precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA® stands behind every Resonator with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.