2 fine/very fine used singles on piece & empty booklet of the 25c red Military from the 1940-1941 War Savings Issue.
As explained in the book, 1 page containing 16stamps issued for $4 could be traded for $5 War Savings certificate, which could be redeemed after the war. So the Gov't was borrowing $5 to pay for the war effort and repaying $5. Each book had 5 double sided pages worth a total of$25 for $20 spent. The booklet has some minor stains &1 loose page.
Van Dam doesn't list these varieties, so we estimate them at $35. The stamps offered here grade 70 and 75 as follows:
