These 9" x 12" Clear View Poly Mailers feature a self-seal closure. These clear view co-ex poly mailers envelopes are an ideal solution for sending and displaying literature, catalogs, and brochures. These clear view poly mailers, made of tear-resistant 3 mil polyethylene, have a clear front for viewing contents and an opaque back for address information and postage. 9 in x 12 in .0025 Poly mailer envelopes are commonly used for shipping a wide variety of individual goods like paperwork, small books, apparel, accessories, fabrics, and more. Our clear view poly mailers are the ultimate in quality and lightweight for low-cost postage, 500 per case.