Almost finished a complete bathroom remodel. Tile floor already installed and painting complete. Going to install toilet and realize this is the flange I have to work with (see pictures). Looks as if bolt slots are in tact, but I haven't seen a flange like this anywhere in pictures and videos online. What kind of flange is this? Can I use this existing (concrete?) flange? Any risks with re-using the existing? If I can't use it, what needs to be done in order to replace with a new flange?
