Our poly mailers are made of new raw material,and has got the ROSH certification.And the thickness is good enough to protect the packing products in the express delivery.The adhesive flap is sticky enough to protect your privacy.Waterproof when it\'s been delivered. Specification： Usable size: 10x13 inch, outside size: 10x13+1.6inch Pack: 25pcs poly mailers included Color: Gold lettering on white THICKNESS: 2.5 Mil thick heavy-duty Feature description： 【SAVE YOUR TIME AND SHIPPING COST】 【Waterproof】 【Durable Protection】 【high-quality】 【100% Satisfactory Service】:We are responsible for every poly mailers sold.If you have any product problems,please contact us.Our service team will respond quickly to your problems within 24 hours.