1.2.1 First Class Mail – Letters and Postcards This contract includes letters and postcards up to three ounces. Letter size mail is rectangular in shape and consists of letters within the following dimensions: Minimum Length – 5 inches Height – 3-1/2 inches Thickness - .007 inches Maximum Length – 11-1/2 inches Height – 6-1/8 inches Thickness - .25 inches Postcard size mail is rectangular in shape and consists of postcards within the following dimensions: Minimum Length – 5 inches Height – 3-1/2 inches Thickness - .007 inches Maximum Length – 9 inches Height – 6 inches Thickness - .016 inches 1.2.2 First Class Mail - Flats This contract includes flats up to 13 ounces. Flat size mail is rectangular in shape, uniformly thick, flexible and consists of mail pieces within the following dimensions: Minimum Length – 11-1/2 inches Height – 6-1/8 inches Thickness - .25 inches Maximum Length – 12 inches Height – 9 inches Thickness - .75inches
