A reproduction of a World War II-era poster publicizing V-Mail, available at the website of the Minnesota Historical Society.
And another. Americans first began using V-Mail — “Victory Mail” — in early 1943. Correspondents wrote letters on specially sized forms, which were then microfilmed; the rolls of microfilm took up less space than regular mail, leaving more room on transports for military supplies. Overseas, the microfilmed letters were enlarged and printed on paper for their recipients. By the end of the war, home front writers had sent more than 500 million V-Mail letters to troops overseas.