3M™ Non-Printed Zipper Closure Packing List Envelope NPZ-L is a 8.5 in x 11.5 in unprinted, clear polyethylene envelope with a zipper closure for easy and secure open and close. This envelope is designed with a high-tack rubber resin adhesive that sticks on contact to packages. Oil- and water-resistant, this packing list envelope securely protects documents from damage throughout delivery.Keep packing slips, invoices, catalogues, cards and other shipping documents safe and secure with 3M Non-Printed Zipper Closure Packing List Envelope NPZ-L. This 8.5 in x 11.5 in, clear, polyethylene envelope comes with a zipper closure for open-close and re-open convenience, and a high-tack rubber resin adhesive that sticks immediately upon contact. Oil- and water-resistant, the 3M Non-Printed Zipper Closure Packing List Envelope NPZ-L is built to withstand the toughest handling conditions.