4 1/2 x 5 1/2" Yellow "Packing List Enclosed" Envelopes. Pressure sensitive packing list envelopes secure and protect documents that are attached to the outside of shipments. Full face, colored Packing List Envelopes are pre-printed with "Packing List Enclosed" on heavy 2 Mil poly. Hot melt adhesive backing provides strong adhesion to paper and corrugated products. Envelopes open along the first dimension.