Borla 40945 XR-1 Stainless Sportsman Racing Oval Muffler Made of corrosion resistant aircraft quality stainless steel which decreases the fatigue incurred on these parts during high performance uses BORLA uses patented straight-through and multi-core technology to help increase horsepower and torque. Precision manufactured using aircraft-quality stainless steel, guaranteed to look like new for one million miles. Inlet Diameter: 3 1/2" Outlet Diameter: 3 1/2" Case Size: 12" x 4 1/2" x 7 7/8"