29-2p2x, 1929 U.S. Christmas Seals, Imperforate Proof Sheet, F, No Gum. Fresh, firm paper, vibrant colors, never folded, shipped flat.
Issued 1929 by the National Tuberculosis Association (NTA). Designed by George V. Curtis. Bell ringer design. Sheet of 100 (10x10). Printers Mark: a dark dot in the lower left hand corner of seal #92.
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.