Envelopes that may save money in postage costs based on the USPS new shape-based rate structure. Postage costs can be greatly reduced by changing a flat mailer to a letter rate by using Quality Park's specially sized envelopes! Sized to accommodate a greater number of pages when sheets are folded. Security tinted for privacy of contents. Envelope Size: 6 x 9 1/2; Envelope/Mailer Type: Business/Trade; Closure: Gummed Flap; Seam Type: Traditional.