Applicability of the New Rules. The new cargo securement rules apply to the same types of vehicles and cargo as the old rules, covering all cargo-carrying commercial motor vehicles (as defined in 49 CFR 390.5) operated in interstate commerce.
Most commercially-produced postcards measure approximately 4.21 inches by 5.47 inches. Less commonly, smaller postcards are typically 3.5 inches by 5.5 inches, close to the minimum size the USPS allows.
The pieces are designed to be bigger than a post card so they stand out in your mail. A post card is $.34 and an EDDM pice, no mater the size (max is 12 by 15) it is only $.175 or about half the cost of a post card. There is no address at all.