Radio frequency proximity tag

Radio frequency proximity keychain (Tag).
It allows the automatic identification of the user by radio frequency, RFID. Passive tag contains a chip that when approached to the reader receives an induced current that activates it. When activated it returns an identification code to the system, therefore it does not require any battery.
It communicates with the reader through a low frequency radio antenna at 125 KHz.
It has a keychain format with a plastic body and metal rings.
Specifications
     RFID: 25KHz passive
     Material: PVC and metal rings
     Dimensions: 58 (H) x 27 (W) mm
     Weight: 5g