This is a replacement cat, and is about half the size of the original. Note the tube coming out the side, through a high-temperature silicone adapter tube (green), and then forward to hook up with the original Pulse Air tube coming from the "Downstream" checkvalve at the engine. It has been my experience after two replacements that these supposedly high temperature rubber tubes do not last, but disintegrate very quickly due to the high temperature at that location. A much better solution is an aftermarket kit that contains a long copper tube and clamps to move the rubber adapter farther away from the cat itself.