26-2xA, WX38, 1926 U.S. Christmas Seals Sheet, Type 2, F, No Gum. Sheet has never been folded, shipped flat. Sheet has been reinforced.
Issued 1926 by the National Tuberculosis Association. Designed by George V. Curtis. Image of the Cross of Lorraine on Shield. Offset by United States Printing & Lithograph Co. Sheet of 100 (10x10), SE4S, blue, red, yellow, and black. Seal size: 18x24mm, pefr. 121/2, no gum.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.