High Quality Self Sealing Poly Courier Shipping Mailers! These mailers are approved by UPS, FedEx & USPS. The mailers feature a superior tear and puncture resistance. The dark inner layer inside of the mailer provides confidentiality. Pressure sensitive adhesive provides a high strength durable closure. Poly mailers are perfect for shipping a wide variety of non-fragile items. High strength seams allow for over-stuffing. The mailers are lightweight and save on postage.