Replace your factory o2 housing with this cast stainless steel piece. Will virtually last forever, bolts in place of the stock piece, works with the K04, z54, or ZFR turbos. The downpipe bolts to this and then bolts to your catback exhaust.
This uses the same gasket for the inlet and outlet, it can come with the gaskets if you select them. Sometimes the OEM gasket can be reused.
Fits the 2.0 liter Cobalt and HHR.