Proximity radio frequency tags (tags). It allows you to identify RFID users. passive tag, contains a chip that is near the reader receives an induced current that activates it. When activated, it returns an identification code to the system so it does not require any battery. It communicates with the player via a 125 kHz low frequency radio antenna. Maximum security, non-copyable devices. RFID 125 KHz PassivePVC material and metal ringsDimensions 58 (Al) x 27 (An) mmWeight 5 g Key Proximity TAGRFID IDPassive RFIDLow frequency 125 kHzLightweight and portableMaximum security