This type of plastic bag/envelope was developed in the early 1980's to improve the secure transfer of bank notes between retail sites and the banks. Cash in Transit carriers were experiencing cash losses which could not be traced to a specific person, so the company carried the cost and a criminal in their ranks. The introduction of Tamper Evident Bags (cash bags) meant that as soon as a bag is sealed anyone opening it leaves an obvious trace. This key feature combined with a unique numbering system and tear off numbered receipts (each person in the chain had to inspect the bag and sign it off as un-tampered) meant that losses fell dramatically.
Applications

Tamper Evident bags (also called SealBags)are now used for the collection of forensic evidence at the scene of crime, Visa or Passport transmission, the mailing of exam papers, the secure storage of deeds, secure postage, postage of blood samples, diamond transport, solicitor's mail, hotel valuables, Government department mail, key control (key bags), video tapes....etc.