: A replacement catalytic converter manufactured by aFe Power for the 1996–2000 Toyota 4Runner . It is a single-piece, bolt-on system designed to fit factory mounting locations.
If you are looking for instructions on how to assemble these parts, they are generally considered intended to be installed as single units or standard multi-piece kits by a mechanic.
: While "123997" is sometimes listed in catalogs related to this system, the MicroDock II is a retired test and calibration docking system for gas detectors.