Catalytic Converter

Also known as a catalyst or CAT.

A catalytic converter is a stainless-steel canister that contains a thin layer of catalytic material such as platinum, rhodium or palladium. The canister is mounted under the vehicle as part of the exhaust system, transforming harmful tailpipe emissions into less harmful or completely benign ones. Carbon monoxide is converted to carbon dioxide; nitrogen oxide into nitrogen and oxygen; and hydrocarbons into water.