5 1/2 x 10" "Packing List/Cert of Compliance/Cert. of Analysis Enclosed" Envelopes. Pressure sensitive envelopes secure and protect documents that are attached to the outside of shipments. Pre-printed with "Packing List/Certificate of Compliance/Certificate of Analysis Enclosed" on heavy 2 Mil poly. Hot melt adhesive backing provides strong adhesion to paper and corrugated products. Envelopes open along the first dimension.