What are the required dimensions for the different classes of mail?
Postcards are 3.5″ by 5″ Letters are 6 1/8″ by 11.5″ Flats must have one dimension that is greater than 6-1/8 inches high or 11-½ inches long or ¼ inch thick. They can be no more than 12 inches high x 15 inches long x ¾ inch thick. For more information on letters and cards, please refer to the following link: http://pe.usProperty Services.com/cpim/ftp/manuals/qsg300/q201.pdf For more information on flats, please refer to the following link: http://pe.usProperty Services.com/cpim/ftp/manuals/qsg300/q301.