Edward Gein one page typed letter on sheet music paper in which Gein informs his friend that a recent mailing contained contraband prohibited by the facility. Gein also tells his friend that he is out of writing paper. 
The letter is hand signed at the close, Edward Gein.

Accompanied by the original USPS postmarked mailing envelope with Gein's friend's name and address on the front.

As with any types of collectibles, research what you buy as there are many questionable Gein related items appearing on the market including some which appear to have been addressed to his friend Jeffrey with no envelopes or provenance to back them up.