Poly mailing envelope, 10" X 13" self-seal, plain white. Co-extruded film mailers offer more secure, more durable, more effective shipping for your documents and soft goods. These economical, high-efficiency mailers are perfect for shipping a wide variety of non-fragile items. Features: Opaque inner security layer keeps contents confidential; The 2.5mil three-layer co-extruded polyethylene film is moisture- and puncture-resistant and has exceptional tear strength; Adhesive, tamper-evident self-seal closure with poly-release liner is easy-to-use and ensures a secure closure; Each case contains 10 packs of 100 mailers (1000 per box).