Lot Of 2 US Birds 11.1c Nonprofit Stamped Envelopes

Lot of 2 USPS bird-themed 11.1c nonprofit stamped envelopes, dated 1991 as shown in the photos.

Includes one window envelope and one non-window envelope. Both are unused and in very good pre-owned condition.

A nice addition for collectors of United States postal history, stamped envelopes, or bird-themed postage items.