Antica GRIGLIA DA PAVIMENTO ART DECO 15-5/8" x 11-5/8" SYMONDS MODELLO 241, si apre e si chiude
Probably a SYMONDS MODEL 241. Large floor grate 15-5/8" x 11-5/8". Fits floor rough opening of 16" x 12". Various patent dates including "July 17, (19)17". WYSIWYG (What you see is what you get).