Sierra - Silverado bumper exit cat-back (OEM) model 2019 - 2026 Features and specifications of the BTM cat-back for GMC and Silverado: Resonator size is 3 inches. Resonator valve thickness is 4 mm (thicker than usual valve thicknesses). Benefit: stronger resistance to backfire and pops. BTM cat-back with the device (electronic) 3 inches. One-year warranty on welding. Made of 304 stainless steel and fully TIG welded. Increases engine performance and horsepower. Compatible with Sierra and Silverado models from 2019-2026.