American Standard Yorkville. Which size closet flange do I need?

Hi!

I'm installing an American Standard Yorkville rear outlet floor mount toilet. I have no any flange at the wall before. The horn at the back of the toilet bowl looks like it is 3 1/8 outside diameter or about it.

Which size closet flange do I need?
And which "neoprene seal" (as installation manual says) ring do I need?

Thanks a lot,
Alex

The Yorkville uses a standard closet flange, installed in the wall.
You can use either the neoprene reinforced wax ring specifically mentioned for wall installation, (it has to mention wall installation on the box) or they do make a rubber seal that installs without wax for that purpose. I don't remember the brand right now.