Transponders also called "tags", "markers", "identifiers" thanks to the small integrated circuit can transfer information containing credentials granting users the authorizations specified in the RFID application. Transponders allow you to gain access to functions or guarded zones - buildings or individual rooms, or only lockers, e.g. in changing rooms in swimming pools, fitness clubs, or turnstiles at metro stations.
RFID transponders can be divided into passive ones, i.e. those that operate within the electromagnetic field generated by the reader, and active ones, which, thanks to the batteries, can generate the field themselves, significantly increasing the range of their operation. The profit from the range of active tags also comes at a cost, in the form of the need to periodically replace the coin cell battery.