National Plumbing Supply Center
- Caption: Pittsburgh: National Plumbing Supply Center: World's Largest Pipe and Tube Mill.
- Notes: One of a series of stamps issued by the Pittsburg Dispatch. Top white border damaged; digitally repaired. Size: approximately 2" x 1.5" (5cm x 4cm).
- Date: Approx. 1911-1922.
- From the Collections of the Pennsylvania Department,
- Carnegie Library of Pittsburgh.