Knives P-9 (lower envelope), P-10 (middle envelope) and P-11 (upper envelope) compared. Knife P-9 was used on the
smaller size 5 envelopes. The rounded flap of knife P-10 was used on all of the size 6 envelopes produced in 1884
(the large size 10 envelopes used for some of the 10c value had knife P-12 - not shown), as well as the 1885
printing of the 1¢ value, discussed below. The pointed flap of knife P-11 was used in printings to fulfill
printings of the 1¢ and 2¢ values beginning in 1889, discussed below. Notice also the difference in the corner
angles where the flap meets the body of the envelope. Knife P-11 has a wider angle.
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