it is made of plastic and says sequential fuel injection on the back of it. and it covers the rail and injectors/harness. these are found on 1984-1985 buick turbo riviera's.
I have one of these, but if you're looking to put it on an '84 GN, I don't think it will clear the turbo mounting bracket on the passenger's side, and will likely melt near the hot side turbo inlet pipe.