These self-seal 10" x 13" Blue Poly Mailers are the perfect packaging material to protect your products from moisture during shipping while also setting your business apart with a nice colored poly mailer. Just add your custom label. Blue Colored Poly Mailers are Moisture resistant, Puncture resistant, Tamper evident and Tear resistant. The inner lining is silver which further blocks the contents you have packaged. 10 in x 13 in .0025 Blue Poly mailer envelopes are commonly used for shipping a wide variety of individual goods like clothing, bedding, paper work, books, shoes, apparel, accessories, fabrics, and blueprints.