A blue sheet of stationary that folds into an envelope.
Context
There is no 'to' or 'from' information. It is postmarked PHILADELPHIA, PA DEC 13 1971. The top of the page is the shadow of a flight of birds next to 'usa postage 15¢' imbedded stamp. Below it reads 'FIRST DAY OF ISSUE'. There are directions for the folding and sealing of the envelope on the sides and in between the sections.