An antique (or very near to antique) wall mirror with a very slight bevel and copper clips holding it against the backing. This beaut was certified to be genuine plate glass and is guaranteed against silver spoilage by the White Seid Products Co out of Baltimore, at least according to the maker's mark on the back, right next to the hangwire. I tried searching for any more information, but it seems that White Seid Products left only a handful of mirrors on Etsy as the only marker of their existence.