This simple, stylized stamp was used to pay the basic rate for first-class mail that had been presorted according to ZIP code. Its graphic design features the letters USA, which appear to be made out of chrome. Reflected on their metallic surface is the red, white, and blue of the windblown American flag. Printings by two different companies, the Bureau of Engraving and Printing and the American Bank Note Company, resulted in distinct color differences. In 1993, a third company, Stamp Venturers, printed this stamp using a three-color gravure process (as opposed to a 4-color process), which resulted in yet another variety.