sealing,fastness,good security,handy use. Mailing envelopes also named courier bags,experess bags,mailing bag-fastsealing,fastness,good security,handy ... design for buyer)Application:to pack shoping or posted by courier industry or retailer.Character:double ealing lips with easy-tear ... to seal the article for returning by buyer. Mailing envelops/Courier bag/Destructive envelope bag