5 p green A eagle type 1901-1911

5p green (example image: 56A)

Different types of this stamp:
48 Emergency issue, 14 1/4 x 14 3/4, 1901
50 First issue of type 1901 lithography, 14 1/4 x 14 3/4, 1901
56A Letterpress I typography, 14 1/4 x 14, 1906
56B Letterpress I typography, 14 1/4 x 14 3/4, 1901

Emergency issue 1901: Dull green. Outer framelines are close together. Arrowheads on posthorn are (usually) blunt.
First issue 1901: Outer framelines are close together.
Letterpress I 1901/1906, a clear white space separates outer framelines.