The OEM Quality Park Poly Expansion Mailers come in a carton of 100 and are designed for durability and moisture resistance. These mailers are ideal for bulky mailings, featuring high-density polyethylene construction that is significantly stronger than paper. The convenient Redi-Strip closure allows for easy sealing; simply peel off the strip and fold the flap closed. The pressure-sensitive gum forms a permanent bond, ensuring your items are securely packaged.