What's the difference between "direct fit" and "universal" catalytic converters?

A direct fit catalytic converter directly replaces your original equipment.  The old unit can be unbolted and removed, and the direct fit replacement bolted in its place.


A universal catalytic converter is a bit misleading of a name.  These units must still be selected for your specific vehicle and engine.  Unlike direct fit units, they do not come with bolt holes and flanges.  The old units must be cut out of your exhaust system, and the universal unit is then welded into place.


Some catalytic converters are listed as "OEM grade". What does this mean?

OEM grade refers to the loading of precious metals in the unit. Generally, the more precious metals in the unit, the better that unit is able to convert harmful exhaust into water and carbon dioxide. OEM grade units are generally preferred for engines with California emissions standards.