courier bag andmailing bag, express delivery bag, mailerbag, post envelope: materialLDPE or HDPE coextrusion materialthickness0.06-0.12mmbag size35*45+5cm flapsealpermanent adhesive sealprintingcopperplate printing 1)Strict quality control, with ISO9001:2008quality certification, SGS certification. 2) Printing: 1-10 colors, both printed by copperplate printing and non-printed. 3) Material: LDPE or HDPE coextrusion material, outside-white and inside-grey color, 0.06-0.1mm thickness, good security feature and anti-moisture, shockproof, can be recycled.