I bought a catalitic converter from kragen auto parts and began to hear a rattling sound coming from it a month later. I exchanged it and the same sound reapeared in about the same time. I took it off an turned it upside down and these little black pellets fell right out onto the ground. That was a piece of
sh*t of a catalitic. Some parts must be high quality. I immediately bought a
catalitic from IPD and no rattle no problems.