These Thunderbolt universal spun metallic catalytic converters utilize the revolutionary new catalyst technology. Using new manufacturing technology, Thunderbolt fabricates each converter body from a single CNC-formed and laser-welded tubular section, which is then spun into a round converter body shape. The Thunderbolt universal spun metallic catalytic converters are literally manufactured around the catalyst, which is securely tucked inside and necks down to thicker-gauge material at the inlet/oulet for maximum durability. They are available in different-diameter inlets and outlets to match your specific exhaust system. Whether you need centered, offset, or angled, these universal spun metallic catalytic converters will fit any application. as illustrated in the photo you can see the metalic converter on the right is a much higher flowing unite