The PPE 116120000 Replacement Up-Pipes for your 2001-2015 GM 6.6L Duramax increase flow, and reliability. Even a stock Duramax can produce high temperatures and pressures that cause OEM up pipes eventually fail from constant temperature and pressure fluctuation. PPE has taken the OEM replacement to a new level. PPE OEM Up-Pipes allow 53% greater flow over stock, and are a direct bolt-on to your factory manifolds. But unlike factory parts, PPE OEM Up-Pipes are manufactured from 11 gauge 304 stainless steel and include PPE's superior 304 stainless steel, internally-sleeved bellows that can take the abuse of high temperatures and pressures. Uses stock exhaust manifolds and hardware.Features: •Bolt-On Replacement (Non-EGR)•Faster Spool-Up & Increased Performance •Significant Reduction In Exhaust Back Pressure •Free-Flowing Stainless Steel Inner Liner Bellows •Stainless steel 11-gauge .120-inch wall, 2-inch OD Up-PipesDoes not retain use of Egr