U.S. #5211 Total Eclipse of the Sun, PNB of 4
U.S. #5211 Total Eclipse of the Sun, Plate Block of 4
In the first U.S. stamp application of thermochromic ink, the Total Solar Eclipse stamps reveal a second image when the ink is activated by the heat of a thumb touching the stamp image
Code: USPB5211*Counter
Price: $7.20