This is an aluminum Fuel tank top riser.
If you are planning on doing a surge tank, this will allow you to use -6AN fittings for the surge tank.
You will need rubber fuel lines from the OE tank cover to the barb fittings.
It Will also help from your fuel hose getting pinched, when trying to route the hose into trunk. Fits directly over the existing cover in your trunk.
Remove OEM Piece and use this to bolt directly over the factory location.
This will make your surge tank install cleaner and easier.