SEWING PATTERN SELLERS- You cant send a pattern first class with delivery confirmation unless its at least 1/4 inches thick, & not more than 3/4. If it isnt at least 1/4in thick, they consider it to be a flat, and/or letter. They then bump it up to Priority mail, and your buyer then gets stuck paying an additional 3.00+. So, leave off delivery confirmation, or make sure its at least 1/4 in thick by adding tissue, bubble wrap, cardboard, whatever. I just went three rounds with the main USPS over this, when I had to pay an additional 7 dollars to get two patterns that were mailed to me.