It's envelopes 176, 177 and 179, sent to Jan H, Smash and Jean W, addressed in vertical format. The scans didn't come out nearly as nicely as the envelopes themselves, unfortunately. Jean will most likely blog this, so maybe her scanner will do a better job.
Stamped with C. Alfred "Chief" Anderson. The scanner seems to pick up the stamp color and emphasize it more than on the envelope (it is not an exact match, but looks less prominent in reality).
And the reverse sides: