Each bag is made from durable 2 mil polyethylene plastic to resist tears, punctures, and damage from liquids, dirt, and dust. The poly mailers also feature our self-sealing adhesive closure. High-strength closure guaranteed to keep your items safe. At 10 x 13 inches, you can easily mail t-shirts, socks, napkins, fabric, yarn, dress shirts, and more easily and efficiently. The poly mailers are durable yet lightweight, making them a great option for every type of business.