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USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios
![USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios](https://www.mitostudios.com/wp-content/uploads/2012/01/usps_phx_domestic_letters.jpg)
USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios
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Greeting Card Shipping Upgrade, USPS First-class With Tracking Upgrade for US Purchases of 1-2 Cards - Etsy
![USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios USPS Mailing Guidelines for First Class Mail - Letters, Postcards, Envelopes & Packages - MITO Studios](https://www.mitostudios.com/wp-content/uploads/2012/01/usps_phx_domestic_postcards.jpg)