A non-denominated postage stamp (eighteen cents) in B series was issued in San Francisco, California on March 15, 1981. This stamp was intended for domestic use only.
The stamp design was originally used on the 8-cent embossed stamped envelope designed by Bradbury Thompson and issued in May 1971. The stamp was issued in a pane of 100, and coils of 100, 500, and 3,000, and a book of 24.
Postal Bulletin (March 20, 1981).