USPS Priority Mail Flat Rate Envelope 12 1/2" x 9 1/2" Ship any weight domestically for only $4.95 (Domestic Priority Mail). Ship up to 4 pounds for only $10.40 (Canada and Mexico), or $12.30 (all other countries) by International Priority Mail Postal rates are subject to change Each pack contains 10 envelopes Maximum order quantity is 60 packs Large orders will be fulfilled as permitted by postal regulations