This picture shows two different colored "knob" dome CD 127's embossed "W. Brookfield 55 Fulton St" on the front dome and "Pat April 4 1871" on the back dome versus the rare "mushroom" dome "Pat Apl 4 1871" mould variant which has a lip on the lower wire groove. This picture contrasts the green, aqua, and blue colors and the two style variants for the CD 127 April 1871 date. You will note that in the next series of pictures that the April 1871 dated CD 127's are different than the April 1870 dated CD 127's.