This knob, made in two styles and two sizes, is based in design patent #D7378, April 14, 1874 by Burton Mallory. Cast bronze or iron. In 1882 catalog, page 262 and 1876 catalog, page 325. Pictured is the 2 1/4 inch size. The larger size knob has the addition of a row of triangles on each side of the edge band.K-11400is the other style in the 2 1/2 inch size.