Is anyone else on the forum interested in US savings bonds? There is a postal connection: savings bonds were initially sold "at retail" only over a post office counter - the post office was the original exclusive agent. And, of course, the 1940 and subsequent issues of postal savings, war savings, and savings stamps were primarily issued to facilitate savings towards bonds.
Had to share this one. Pre-Pearl Harbor bonds are quite scarce; this was a happy recent eBay
find. There are two varieties of the Series E "defense" bonds - the early ones have rouletting at the top; the later ones at the left. Series A-D bonds are rare.