This is a gem! 1907-1.2, 1907 U.S. Red Cross Christmas Seals Block, thin paper variety, block of 16, VF, MNH. Seal size 19x19mm, perf. 14. Great centering. Image of Red Cross, with text "Merry Christmas"
The 1907 Christmas Seal was issued by the Delaware Chapter of the American Red Cross. There were two types: Type 1 - "Merry Christmas," and Type 2 - "Merry Christmas / Happy New Year." This seal is a Type 1, thin paper variety. The 1907 Christmas Seal was designed by Ms. Emily P. Bissell.
Christmas Seals are also known as TB Charity Seals, and are usually classified as Charity Seals, or Cinderella Stamps.