19-2x, WX24c, 1919 U.S. Red Cross Christmas Seals Sheet, Type 2, full gum, F, NH. Never folded, shipped flat. Scan of front and back.
Issued 1919 by the American National Red Cross. Designed by Ernest Hamlin Baker. Lithographed by Strobridge Lithographing Co. Image of Santa, white dot on Santa's cap, carmine, and blue. Sheet of 100 (10x10), SE4S. Seal size: 18x22mm, perf. 121/2, full gum.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.