The lightweight mailer, made of materials, is good for shipping and express. It is much stronger than paper envelope, providing the best protection for shaped and irregular items during transportation in rainy days. Effectively add protection and cushioning by protecting your items from any vibration, scratches and dings. Features -Color: Blue. -Material: Co-extrusion film, film. -Size: About 23x18x4cm/9.04x7.07x1.57 inch. - envelope. The thickened envelope is light and waterproof. Reduce business costs and protect your products in rain or snow. -Self-sealing packaging. The adhesive on the is strong enough to stick it from end to end. No reinforcement tape is needed, and it won’t be taken apart unless you . -Cushion mailing bag. These are blue mailing envelopes with enough padding to mail items that need protection. Ensure product safety. -Mail supplies. The envelope is very strong and you can mail books and other items. The quality of the mailer will remain in good condition during transportation. -The outer layer is a blue polyester film. The envelope feels good to the touch and is handwriting, labeling and stamping. Package list: 25 x