500 Double-Sided, Full Color Mailers on USPS Required .007 inch thick cardstock. *These mail pieces are USPS specification approved for EDDM (Every Door Direct Mail) Program. Same or next business day service! Shipped Priority Mail® Medium Flat Rate Box $12.35 (with 2 day expected delivery) You will be prompted to upload your file upon completion of checkout. 8-1/2" x 11" no bleeds.