The 6-cent Abraham Lincoln of the 1873 Issue looks identical to its National Bank Note Company counterpart except for two major distinguishing features. Continental Bank Note Company’s stamp has a dull pink ink color and a secret mark; the NBNCo ink color is carmine. The secret mark can be seen at the stamp's bottom left. Below the word ‘six’ there are two ribbons whose ends curve toward the bottom of the ‘x’. At the point where they curve, there are four vertical lines that are heavily shaded.
Until the five-cent U.P.U. rate was established in 1875, the 6-cent Lincoln would have paid the half-ounce rates to many countries, including Great Britain and Canada, or in combination with other denominations, higher postal rates. Its most popular domestic use paid the double-weight first-class rate. Continental Bank Note Company printed approximately 47,000,000 of its 6-cent stamp.