If you look carefully at the last picture in post 42 of
this thread, you can see the rusty old one I had. It's incompatible with today's power cords at any parks. That said, you can have my old one for the cost of postage -- I wouldn't recommend it.
Instead, I really like the Marinco Stainless inlet. They are threaded and mate to a power cord that will have the correct 30 amp plug at the RV park. Search eBay for "Marinco 30amp stainless" and you'll see some decent prices on them.
Most of us have put an Alclad patch over that hole and moved the inlet elsewhere when rewiring the trailer.