1918-2.p, 1918 U.S. National Christmas Seals Imperforate Block, VF, MNH. Fresh, full gum, and vibrant colors.
Imperforate proof in block of four (4), from top margin. 1918 Type 2 seals were not issued in sheets of 100.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.