Introduced in 1896 instead ofB-21400as part of the modified Columbian design. Shown in 1996 catalog page 253, 1897 catalog pages 153 & 253, 1899 catalog page 228, 1900 catalog page 258 and 1911 catalog page 258. A detailed study of this knob reveals the four-fold nature of the design and so it is also shown on the H page.