This 2.5" diameter into dual 2.25" BORLA® Cat-Back™ system was specifically designed to enhance the power and sound of the Frontier equipped with 3.8L engine. The system features the classic S-Type sound that gives you a powerful performance sound with no drone. It features 2 full Tail Pipes (Not a single tail pipe with dual tips) with single 4" round black chrome on T-304 stainless steel tips on each tail pipe and a dual side exit configuration. Using BORLA® Stainless Steel Polish p# 21499 is NOT recommended with these black chrome tips. We suggest cleaning the tips with hot water and a microfiber cloth. A system is also available with bright chrome on T-304 stainless steel tips. Borla® Cat-Back™ & Axle-Back exhaust systems feature patented straight-through and multi-core technology to unleash hidden horsepower. Increased exhaust velocity adds power, driving excitement, fuel economy, and the distinctive BORLA® Sound of Power respected by motoring enthusiasts everywhere. Each system is built from premium, high-quality T-304 austenitic stainless steel, superior to T-400 series knockoffs (such as 409), to give you the absolute best in performance and durability. The entire system is made of T-304 stainless steel and utilizes computer numerical control (CNC) manufacturing techniques that ensure an accurate fit. All this is backed by our unsurpassed Million Mile Warranty. System Features:; Cat-Back™ System; Dual Side Exit; 4" Round Black Chrome On T-304 Stainless Steel Tips; S-Type Sound Level; T-304 Stainless Steel Construction; Bolt-On Installation; Million Mile Warranty