The listing, 1 1/2¢ Harding, 'Bureau' Pre-Cancel: PITTSBURG PA. has ended.
On Scott #598, this is an example of a US Bureau of Engraving and Printing's Pre-Cancel:
PITTSBURGH PA.
[1 of 76 different 'Bureau' pre-cancels on this stamp]
These were tested in several cities and were used to reduce handling and to speed -up the mail.
A special permit is required for use of these by the public (except for such notable examples as the 1969 6-cent Christmas stamp (designed by Stevan Dohanos) and later Christmas mail issues).
Definitive Issue of 1923-29
1 1/2 Cent - President Warren G. Harding
(beginning: March 19, 1925) Scott #598
Rotary press printed coil stamp - Perf. 10 Vertically
Condition: USED