Qline tamper proof courier bags are made of Co-Extruded Polyethylene Films, which are black on the inside and white on the outside,Transparent bags and have a flap with a hot melt adhesive strip for quick and permanent sealing. Once sealed, the envelope cannot be opened; the only way to open it is to rip or cut it. On either side of the envelope, a clear overlapping pod jacket for inserting waybills or consignment notes, etc. is available.