Selling a Vintage pair of Envelopes advertising The U.S. Steel Works Corp aka Irvin Works, "The Largest Hot Strip Mall in the World" that was located in Clairton, Pennsylvania. The envelopes are considered "used" but have never been written on. They are ages and have discoloration marks to show from it. The envelopes have sealed and also have some silverfish holes. 3ach envelope measures approximately 6  1/2" x 3  5/8". Please feel free to message me with any questions or requests for more photos. Selling as is as shown in photos and description. Thanks