We classify this knob as the Art Deco era, but it could be older. It is a “drum” shaped knob, one that is wide, narrow, and flat across the top. It has the circle pattern on both the surface of the knob (2 cut-in rings) and on the side (3 cut-in rings).
The knob measures 2 1/4 inches across and 5/8 inch deep. It is heavy cast brass (or bronze).
This is a very fine door knob. It is in excellent condition. We have left it as is–no polishing or cleaning. It maintains its old patina.