1941-1px1, 1941 U.S. National Christmas Seals, Imperforate Proof Sheet, pm "E", F, No Gum. Issued 1941 by the National Tuberculosis Association (NTA). Designed by Stevan Dohanos. Image of a lighthouse and snow. Firm paper, fresh, never folded, shipped flat.
Sheet of 100 (10x10) seals. Colors: yellow, black, red, and blue. Seals Size: 171/2x271/2. Printed by the Eureka Specialty Printing Co.
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.