This NFC key fob contains 2 RFID Chips and Antennas. It has a UID changeable S50 Mifare Classic 1K chip and a T5577 ID Changeable chip.
The UID of the Mifare 1K chip can be modified by ACR122U, PN532, PCR532, Proxmark3 X, iCopy-XS.
The ID of the T5577 chip can be modified by Proxmark3 X and iCopy-XS.
With this Combo Key Fob, you can easily access 2 door system under different frequency easily.