Choose Booklet Envelopes for sending large pieces of business communication. The flap on the long side of the envelope makes it easy to enclose a brochure, catalog, or thick stack of paper. Booklet Envelopes are available in a wide range of sizes, including 6 x 9, 9 x 12, and 10 x 13. The most popular sizes offer many colors to choose from to help coordinate envelopes with the visual branding of a business. All of our Booklet Envelopes have custom printing available!