This is a special font for use creating US Postal Service "Intelligent Mail" barcodes. Those are the barcodes you see on most cards and envelopes. Commercial mailers get the best pricing by printing barcodes when they address the mail, saving the Postal Service a step. The barcodes are also used on reply mail and Share mail, and for "Informed Visibility" tracking.
Software to create these barcodes typically provide an output of 65 characters, each character being an A, D, T or F, corresponding to each of the styles of bar. SmartBars 12 replaces those characters with the corresponding bar. When doing a mail merge to print addresses, the user would set the barcode field on their merge template to be printed using SmartBars 12, at 12 point, regular, and the barcode will print with the correct bars and at the required size to meet USPS requirements.