Experience the power of the disc. Highly polished t-304 stainless with a corrosion resistant stainless steel perforated core. Add 4 discs to increase horsepower, exhaust tone and flow. Remove 4 discs to reduce sound and increase low-end torque. The 17 length comes with an id of 2.50 and include a center pull clamp. Extra 6-pack of discs part number r4046506.