Nissan OEM 5-Bolt Metal Turbo Turbine Outlet Gasket

Nissan OEM SR20DET Turbo Turbine Outlet Gasket

This is the gasket that sits in the exhaust side turbine to the O2 extension

The OEM Nissan item is much better than the cheaper gasket commonly found on lower end turbo kits.    

Multi-layer design seals better than cheap paper type.