U.S. #2150a Precancel
1985 21.1¢ Sealed Envelopes
Issue Date: October 22, 1985
City: Washington, DC
Quantity: 14,000,000
Printed By: Bureau of Engraving and Printing
Printing Method: Photogravure
Perforations: 10 vertical
Color: Multicolored
This stamp was issued for non-presorted first-class. "ZIP" stands for Zoning Improvement Plan and was begun in 1963 to improve the speed of mail processing. In 1978, the Zip+4 was introduced. These extra four digits, primarily for businesses, extended a mailing discount to those using a nine-digit ZIP Code. Although an individual mailing 250 items at one time could use the 21.1¢ rate, he would have to meet the same requirements that apply to business mailers.