This is a rare antique square glass architectural house door door knob vintage, . The knob is about 2 1/8 square. Mounts on a square shaft standard size. I have 100's of the normal standard pattern of glass knobs over the years , this is the first square one i had ever seen up till another set this year,, so i believe this are rare, . So here is your chance to own one or 2.This is an antique or vintage used pc so there is a couple of very small flea bites on the raised center of the knob. If you have any questions just ask a-89. This item is made of steel, meta, glass, brass and patina.