23-1x, WX31c, 1923 U.S. National Christmas Seals, F, No Gum, and reinforced. Sheet has never been folded, shipped flat.
Issued 1923 by the National Tuberculosis Association. Designed by Rudolph Ruzicka. image of a child sitting in front of fireplace with Santa peering out. Typographed by Eureka Specialty Printing Co. Sheet of 100 (10x10), SE4S, Seal size: 18x24mm, perf. 121/2, no gum.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.