The EM Proximity Card (HID FARGO TK4100) is 125 kHz RFID card technology. It offers both thick (Clamshell card) and thin (ISO) cards, which are read-only cards.
Each of the EM proximity cards is HID FARGO RFID Card TK4100 which has a unique serial number. It is a great solution for access control, a time attendance system that does not require a very high security level.