Made of courier/mailing/express/postal bag: Courier/mailing/express bags are manufactured from 60-100micron thickness to extruded polyethylene film(Fresh HDPE&LDPE material),which is gray/black inside&white outside(colour can be changed as per requirement). The bags contains a flap which has a hot melt adhesive strip for easy&permanent closure.and designed an open one side flap for protecting goods security,which an adhesive that is applied to the seal flap and is covered with a release liner. When the envelope is ready to be sealed, the release liner is removed to expose the self-adhesive tape. The self-adhesive tape will immediately sealing the plastic envelopes and firmly sealed. Side pocket is also available at the back of the courier/mailing/express bags to insert the shipping label.