These Columbian 10 x 13 Inch Catalog Envelopes have a security tint for private large document storage and mailing. These professional-looking business envelopes are made from durable white wove paper. 28 lb Heavyweight white wove secures your enclosures in a crisp, bright white mailer. For privacy, our security envelopes have a blue tint with safety pattern to prevent prying eyes from reading sensitive information, even when held to light. Too busy to wet-sponge your way through stacks of waiting mail? Release & Seal envelopes are affordable self-sealing options that don't require moisture. A peelable paper strip protects the adhesive from dust so your envelopes last longer in storage. Just peel, press and go. Use 10" x 13" envelopes to fit thick stacks of letter-size papers, legal documents, contracts, catalogs, photos, and other materials you prefer to mail flat without folds. Our 10 x 13 self-sealing stay-flat mailer handles it all! Center-seam catalog-style envelopes open on the short side. You can drop in contents with ease. Great for sorting paper at the desk, in the classroom or in the file room. 100 Per Box.