1971-3px, 1971 U.S. National Christmas Seals, Imperforate Proof Sheet of 100 seals, pm "B", full gum, F, NH. Fresh, firm paper, vibrant colors, never folded, shipped flat. Scan is an example. Full scan of front and back available upon request.
Imperforate sheets have no perforations or rouletting at all.
Issued 1971 by the National Tuberculosis and Respiratory Disease Association (NTRDA). Designed by James Clarke. Eight designs alternate in the sheet; images of men, candles, Christmas trees, and angel. Printed by I.S. Berlin Press.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.