Our Packing List Envelopes are made of pressure sensitive adhesive back, waterproof plastic envelopes with slit backs for easy closure and security. Eliminate need for address labels and protect your packing lists and invoices. Instruction of use: 1. Insert document through slit in back of envelope. 2. Apply to carton by removing lower portion of release paper then press firmly. 3. Peel remaining strip of release paper. Press evenly to secure all 4 sides to the surface.