In 1873, the Post Office began producing a pre-stamped post card. One side was printed with a Liberty-head one-cent stamp design, along with the words "United States Postal Card" and three blank lines provided for the mailing address. Six years later, it introduced a series of seven Postage Due stamps in denominations ranging from 1¢ to 50¢, all printed in the same brownish-red color and conforming to the same uniform and highly utilitarian design, with their denominations rendered in numerals much larger than those found on definitive stamps. The design remained unchanged until 1894, and only four different postage due designs have appeared to date.