TurtlesTradingPost -  Atoms For Peace - Einstein #1070- 1955 FDC Artcraft 

The flap is sealed inside.   No markings on reverse side. Pencil address you can erase if you choose.

We have eight of this very same first day cover as serviced by Ronald Martin in 1955.  They've been together for more than 65 years and are now ready to be sent around the world. Buy one, several or all!