CAR-RT SORT is a United States Postal Service marking appearing above the sendee's address on traditional advertising mail such as store circulars, coupon books, and other bound printed matter (BPD). Advertisers receive a significant postage discount in return for delivering stacks of advertising mail to the postal service that are pre-counted to have the correct number of articles for each carrier's route. Thus the name CAR-RT SORT standing for Carrier Route Sort (or Presort).