That external electric fields can reorient the electric polarization of these materials makes them ideal for certain memory applications, such as stored-value cards used in mass-transit systems.
Besides debit cards linked to a bank account, there exist also stored-value cards (prepaid debit cards) with and without the possibility to recharge them.
Used primarily for payphones, stored-value systems avoid the time lag and expense of communication with a central database, which would have been prohibitive before the 1990s.
Within one year of non-use of stored-value tickets as expired, outdated stored-value tickets available at the station free update procedures for handling customer service center.