Our courier bags are Tamper proof, manufactured from Co-Extruded Polyethylene Films which are black inside and white outside, with a flap that has a hot melt adhesive strip for easy & permanent closure. Once sealed, they cannot be opened. The only way to open is to tear or cut the envelope. A clear overlapping pod jacket for the insertion of waybills or consignment notes, etc. is available on either side of the envelope. Standard sizes are available.