Quality Park - QUAR4611 14 lb. mailer is made of durable, DuPont Tyvek to deliver a high level of protection for your shipments while keeping shipping costs to a minimum. Its expandable design conveniently provides you with extra room to accommodate oversized, bulky items. Flap-stick closure seals tightly without the use of moisture to ensure your contents are securely contained. Mailer is perfect for replacing costly boxes or cartons.