The flexi joint in the exhaust system allows engine movment without putting strain on the exhast system. This replacment section must be welded into the system for a correct fit.
These can occasionally fail, usually due to an inncorrect fitting de-cat/cat pipe to connect the manifold to the catback system. As every car is slightly different we reccomend fabricating a custom pipe to join the two sections together to avoid excess strain on the flexi joint. Please see our Tom-Cat below.