1977-2px, 1977 U.S. National Christmas Seals, Imperforate Proof Sheet of 54 seals, pm "F", full gum, F, MNH. Fresh, firm paper, vibrant colors, never folded, shipped flat. Scan is an example. Full scan of front and back available upon request.
Issued 1977 by the American Lung Association (ALA). Designed by school children from each state plus Puerto Rico, Virgin Islands, D.C. and Guam. Images of children's art. Printed by Fleming-Potter Company.
Imperforate sheets have no perforations or rouletting at all.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.