The old iron beds often had brass bed knobs that threaded,onto the four bed posts. Also, often times, the two,knobs on the head posts were larger than the two on the foot,posts., ,These two knobs are larger than usual and would look ,especially nice at the head posts. They measure 3″ round,,and stand 4″ high.,They are an exact match, but one has 3/8″ threads, ,(check your bed posts with a 3/8″ coarse-thread nut.) while,the other’s threads have been wallowed out. This knob ,would have to set on the post, not threaded onto the post,,or, depending on the bed, rethreaded or packed to fit. , ,We have not cleaned these knobs. One could use brass,polish and really make these shine, if desired. They are in,very good shape. There are only a couple of small dimples,which are not distracting. These are very old.