This concentric bronze door knob is part of the M-18100 group. The set includes two knobs with a spindle, one back plate, and one rosette. This is in great condition. The manufacturer and exact date of creation are unknown. The dimensions are Knob 2.25 in. diameter x 2.2 5 in. D, plate 9.125 in. H x 3.25 in. W x 0.5 in. D, lock hole 1.125 in. diameter, rosette 2 in. diameter.