Good, used Rear Main Seal Retainer Plate for all '90+ 300zx models.
Located on the rear of the engine, this retainer plate houses the rear main seal. These retainer plates can be damaged or broken when improperly installed/removed or when the rear main seal is improperly removed.
There are a total of 3 gaskets that seal against the Rear Main Seal Retainer Plate. All of which can be found new Here.