Transportation coils

The Transportation coils series is a set of definitive stamps issued by the United States Postal Service between 1981 and 1995.

The designs are spare, consisting only of the vehicle itself, and with inscriptions describing the general type ("Circus Wagon" or "Ferryboat") and a date, either a decade or sometimes a specific year.

Some of the denominations also received special service inscriptions in black, such as "Bulk Rate" or "ZIP + 4 Presort".

[2] Many of those denominations were unusual decimal rates, such as 16.7 or 24.1 cents, used by bulk mailers and other businesses[1] who also used precancels.

[2] The series has become popular with stamp collectors, both because of the "classic" engraved designs, and because to the emergence of the plate number collecting.