If your check engine light is on or your Trailblazer's catalytic converter is failing, this direct-fit replacement is a solid fix. It's brand new, unused, and comes in original packaging – retail style unless it's a plain box. Specifically made for 2002-2005 Chevrolet Trailblazer with the 4.2L engine, but it also fits a bunch of other GM SUVs: Buick Rainier (2004-2005), GMC Envoy (2002-2005), Isuzu Ascender (2003-2004), Oldsmobile Bravada (2002-2004), and Saab 9-7x (2005). Important: only fits the 113.0-inch wheelbase models. This cat is EPA OBD II approved, so it meets federal emissions standards, but it's NOT legal for sale or use in California, Colorado, New York, or Maine – sorry, those states have stricter rules. The body is stainless steel with a silver finish, and the substrate inside is ceramic. It's a bolt-on connection (outlet is a 2-bolt welded flange) and comes with bolts and screws for easy installation. No heat shield included. Part number 55476, interchange numbers 19100, 50365, 645878. Unbranded but backed by a strong 5-year manufacturer warranty. If you need a reliable, emissions-friendly cat that won't break the bank, this one does the job. Just double-check your state regulations and wheelbase before buying.